Age is of course a fever chill?: Why even older scientists can make important contributions

A ditty often attributed to Paul Dirac conveys the following warning about doing scientific work in your later years:

Age is of course a fever chill
That every physicist must fear
He is better dead than living still
When past his thirtieth year

Dirac was of course a member of the extraordinary generation of physicists who changed our understanding of the physical world through the development of quantum mechanics in the 1920s and 30s. These men were all in their 20s when they made their revolutionary discoveries, with one glaring exception - Erwin Schrodinger was, by the standards of theoretical physics, a ripe old thirty-eight when he stumbled across the famous equation bearing his name.

When we look at the careers of these individuals we could be forgiven for assuming that if you are past thirty you will probably not make an important contribution to science. The legend of the Young Turks has not quite played out in other fields of science though. Now a paper in PNAS confirms what we suspected, that since the turn of the twentieth century there has been a general increase in the age at which scientists make their important discoveries. What is more surprising is that this increase exists more across time than across fields. The study looks at Nobel Laureates, but since many people who make Nobel Prize worthy discoveries never get the prize, the analysis applies to others too.

So what does the paper find out? It finds out that in the early years of the last century, young men and women made contributions in every field at a relatively young age, often in their twenties. This was most pronounced for theoretical physics. Einstein famously formulated special relativity when he was a 26-year-old patent clerk, and Heisenberg formulated quantum mechanics when he was 24. The same was true for many other physicists including Bohr, Pauli, Dirac and De Broglie and the trend continued into the 70s, although it was less true for chemists and biologists studied by the authors.

The reasons postulated in the paper are probably not too surprising but they illustrate the changing nature of scientific research during the last one hundred years or so. It is easiest for a brilliant individual to make an early contribution to a theoretical field like theoretical physics or mathematics, since achievement in such fields depends more on raw, innate ability than skills gained over time. In an experimental field it's much harder to make early contributions since one needs time to assimilate the large body of experimental work done and to learn the painstaking trade of the experimentalist, an endeavor where patience and perseverance count much more than innate intelligence. As the paper puts it, deductive knowledge lends itself more easily to innate analytical thinking skills visible at a young age than inductive knowledge based on a large body of existing work. This is true even for theoretical physicists where fundamental discoveries have become extremely hard and scarce, and where new ideas depend as much on integrating an extensive set of facts into your thinking process as on "Eureka!" moments. And this difference holds even more starkly for social sciences like economics and psychology where you find very few young people making Nobel Prize winning contributions. In these cases success depends as much on intellectual maturity gained from a thorough assimilation of data about extremely complex systems ("humans") as it does on precocity.

But if this were purely the distinction, then we wouldn't find young people making contributions even to experimental chemistry and biology in the early twentieth century. The reason why this happened is also clear; there was a lot of low-hanging fruit to be picked. So little was known for instance about the molecular components of living organisms that almost every newly discovered vitamin, protein, alkaloid, carbohydrate or steroid could bag its discoverer a Nobel prize. The mean age for achievement was not as early as in theoretical physics, but the contrast is still clear. Even in theoretical physics, the playing field was so rife for new discoveries in the 1930s that in Dirac's words, "even a second-rate physicist could make a first-rate discovery". The paper draws the unsurprising conclusion that there is much more opportunity for a young person to discover something new in a field where little is known.

This conclusion is starkly illustrated in the case of DNA. Watson and Crick are the "original" Young Turks. Watson was only 25 and Crick was in his early thirties when they cracked open the DNA structure, although one has to give Crick a pass since his career was interrupted by the war. What's important to note is that both Watson and Crick came swinging into the field with very little prior knowledge. For instance they both knew very little chemistry. But in this case this lack of knowledge did not really hold them back and in fact freed up their imagination because they were working in a field where there were no experts, where even newcomers could use the right kind of knowledge (crystallography and model building in this case) to make important discoveries. Watson and Crick's story points to a tantalizing thought- that it may yet be possible to make fundamental contributions at a young age to fields in which virgin territory is still widely available. Neuroscience comes to mind right away.

Since this is a chemistry blog, let's look at the authors' conclusions as they apply to chemistry. Linus Pauling provides a very interesting example since he plays into both categories. The "early Pauling" made his famous contributions to chemical bonding in his twenties, and this contribution was definitely more of the deductive kind where you could indulge in much armchair analysis based on principles and approximations drawn from quantum theory. In contrast, contributions by the "late Pauling" are much more inductive. These would include his landmark discovery of the fundamental elements of protein structure (the alpha helix and the beta sheet) and the first description of a disease at a molecular level (sickle cell anemia). Pauling did both these things in his 40s, and both of them needed him to build up from an extensive body of knowledge about crystallography, chemical bonding and biochemistry. It would be hard to imagine even a Linus Pauling deducing protein structure the way he deduced orbital hybridization.

If we move to more inductive fields then the relatively advanced age of the participants is even more obvious. In fact in chemistry, in contrast to mathematics or physics, it's much harder to pinpoint a young revolutionary precisely because chemistry more than physics is an experimental science based on the accumulation of facts. Thus even exceptional chemists are often singled out more for lifelong contributions than for lone flashes of inspiration. Even someone as brilliant as R. B. Woodward (who did make his mark at a young age) was really known for his career-wide contributions to organic synthesis rather than any early idea. It's also interesting that Woodward did make a very important contribution in his late 40s - to the elucidation of the Woodward-Hoffmann rules- and although Hoffmann provided a robust deductive component, inspiration for the rules came to Woodward through anomalies in his synthesis of Vitamin B12 and his vast knowledge of experimental data on pericyclic reactions. Woodward was definitely building up from a lot of inductive knowledge.

An additional factor that the authors don't discuss is the contribution of collaborations. From a general standpoint it has now become very difficult for scientists in any field to make lone significant contributions. In fact one can make a good case that even the widely cited lone contributions to theoretical physics in the 1920s involved constant collaboration and exchange of ideas (mostly through Niels Bohr's institute in Copenhagen). This was far from the case for most of scientific history, when you had people like Cavendish, Lavoisier, Maxwell, Faraday, Kekule and Planck working alone and producing spectacular results. But things have significantly changed, especially in the case of experimental particle physics and genomics where even the most outstanding thinkers can often work only as part of a team. In such cases it may even be meaningless to talk about the young vs advanced age dichotomy since no one individual makes the most important discovery.

Finally, one rather disturbing reason that could potentially contribute to an even greater advancement of age in the context of important discoveries is left undiscussed. As the biologist Bob Weinberg lamented in an editorial a few years ago, the mean age at which new academic researchers receive their first important research grant has been advancing. This means that even brilliant scientists may be held back from making important discoveries simply because they lack the resources. While this trend has really been visible in the last decade or so, it could contribute as an unfortunate factor to the age-corrected generation of novel ideas. One only hopes that this does not make things so bad that scientists are forced to consider contributing to their fields in their 70s.

Ultimately there's one thing that age brings that's hard to replace with raw brilliance, and that's the nebulous but invaluable entity called 'intuition'. As scientific problems become more and more complex and interdisciplinary, it is inevitable that intuition and experience will play more important roles in the divining of new scientific phenomena. And these are definitely a product of age, so there may be something to look forward to when you grow old after all.

Putting the filosophy back into fysiks

How the Hippies Saved Physics: Science, Counterculture, and the Quantum Revival- David Kaiser

Does philosophy have a place in serious science? Many of the founders of modern physics certainly thought so. Einstein, Bohr, Heisenberg and Schrodinger were not just great scientists but they were equally enthusiastic and adept at pondering the philosophical implications of quantum theory. To some extent they were forced to confront such philosophical questions because the world that they were discovering was just so bizarre and otherworldly; particles could be waves and vice versa, cats (at least in principle) could be alive and dead, particles that were separated even by light years appeared to be able to communicate instantaneously with each other, and our knowledge of the subatomic world turned out to be fundamentally probabilistic.

However, as quantum theory matured into a powerful tool for calculation and concrete application, the new generation of physicists in general and American physicists in particular started worrying less about "what it means" and much more about "how to use it". American physicists had always been more pragmatic than their European counterparts and after World War 2, as the center of physics moved from Europe to the United States and as the Cold War necessitated a great application of science to defense, physicists turned completely from the philosophizing type to what was called the "shut up and calculate" kind; as long as quantum mechanics agrees spectacularly with experiment, why worry about what it means? Just learn how to use it. Yet this only swept epistemological questions under the rug.

Curiously, there emerged in the 1970s a quirky and small group of physicists in the Bay Area who tried to resurrect the age of philosopher-scientists. In "How the Hippies Saved Physics", David Kaiser wonderfully tells the very engaging story of this "Fundamental Fysiks" group and how it kept alive some of the deep philosophical questions that had haunted the founding fathers. The "Fysicists" came from a variety of backgrounds, but all of them had been dissatisfied; both by the dismal job market for physicists after the Cold War craze and more importantly by the purely practical approach toward physics which they learnt in graduate school. Interestingly they combined their deep questions about physics with the emerging hippie counterculture of the 60s and 70s and it's pretty clear from the book that they had great fun doing this; after all this was an age when non-conformity was encouraged. Discussions of physics concepts blended seamlessly with Eastern mysticism, forays into LSD-induced mind experiments, New Age workshops at the Esalen Institute in California and meanderings into telepathy, consciousness and parapsychology. Books like Fritjof Capra's "The Tao of Physics" which explored parallels between modern physics and Eastern religions only helped the movement. The small group of physicists was also fortunate to get funding from some unlikely sources, including self-help guru Werner Erhard and even the CIA who was interested in possible connections between ESP and physics. Not surprisingly, mainstream physicists often ignored and sometimes actively condemned such activities

However, as Kaiser describes in this fascinating volume, this ragtag group of countercultural philosopher-scientists achieved at least one crucial goal; they kept questions about the philosophical implications of quantum theory alive at a time when most physicists eschewed and disdained such questions. Gradually, they managed to get a handful of mainstream physicists interested in their philosophizing. Much of the connection of this philosophy to real physics centered about a remarkable result called Bell's theorem which essentially reinforced the spooky properties of quantum systems by showing that information in quantum systems can flow instantaneously between particles. Remarkably, this seemingly otherworldly idea of "quantum entanglement" (which gave some of the founding fathers heartburn) now lies at the foundation of some of the most cutting-edge areas of modern physics, including quantum computation and the new discipline of quantum information science. What was considered far-flung by mainstream physicists and kept alive by the Fundamental Fysiks group is now serious physics for many. In fact, at least a few physicists who put Bell's theorem to experimental test are regarded as candidates for a Nobel Prize (these especially include John Clauser, Alain Aspect and Anton Zeilinger who shared the prestigious Wolf Prize- often a forerunner to the Nobel Prize- in 2010).

In the end Kaiser wants to make the case that by keeping such once-disparaged philosophical concepts alive, the Fundamental Fysicists "saved physics". I am a little skeptical of this claim. They certainly managed to nurture and publicize the concepts, but it was the harnessing of these concepts by "real" physicists who were involved with the nuts and bolts of calculation and experiment that actually saved the concepts and kept them from turning into a purely philosophical mishmash. In addition, a lot of concepts that the New Age physicists bandied about belonged squarely in the realm of pseudoscience and the trend continues; people like Deepak Chopra commit gross violations of quantum mechanics on a daily basis. Unfortunately the line between science and non-science can be thin and one of the most intriguing discussions in Kaiser's book is this so-called "demarcation problem". How does one know if today's philosophy is tomorrow's cutting edge science or just noisy mumbo-jumbo? It's not always easy to say.

Nonetheless, I think Kaiser and the Fysicists make a really great general case for why philosophical questions in science have their own place and should not be rejected. For one thing, they are always fascinating in themselves and demonstrate the endless human quest for meaning and reality; as recent discussions indicate, the philosophical conundrums in physics have been far from answered and continue to be explored through even more bizarre ideas like parallel universes and multiple dimensions. And as this wonderful book shows, at least in some cases these discussions may lead to key advances by influencing mainstream physicists who validate them by subjecting them to the ultimate arbiter of truth in science- hard experiment.

Will-o'-the-wisp around 5 sigma: the hunting of the Higgs

Mr. Hunter, we have rules that are not open to interpretation, personal intuition, gut feelings, hairs on the back of your neck, little devils or angels sitting on your shoulder.... - Capt. Ramsey ('Crimson Tide')

Particle physicists hunting for maddeningly elusive particles sometimes must feel like Mr. Hunter in the movie "Crimson Tide". The quarries which they are trying to mine seem so ephemeral, making their presence known in events with such slim probability margins, victims of nature's capricious dance of energy and matter, that intuition must sometimes seem as important as data. The hunt for such particles signifies some of the most intense efforts in extruding reality from nature's womb that human beings have ever put in.

No other particle exemplifies this uniquely human of all endeavors than the so-called Higgs boson. The man who bears the burden of imparting it its name is now a household name himself. Yet as the history of science often demonstrates, the real story is both more interesting and more complicated. It involves intense competition involving billions of dollars and thousands of careers of a kind rarely seen in science, and stories of glories and follies befitting the great tragedies. In his book "Massive", Ian Sample does a marvelous job of bringing this history to life.

Sample excels at three things. The first is the story of the two great laboratories that have mainly been involved in the race to the finish in discovering nature's building blocks- Fermilab and CERN. CERN was started in the 60s to give a boost to European physics after World War 2. Fermilab was lovingly built by the experimental physicist Robert Wilson, a former member of the Manhattan Project who was a first-rate amateur architect and saw accelerators as aesthetic things of beauty. Secondly, Sample does a nice job of explaining the reasons that led to the construction of these machines, the most complicated that mankind has ever constructed. Only human beings would put billions of dollars and immense manpower on the line purely for the purpose of satisfying man's curiosity of plumbing the depths of nature's deepest secrets. Sample also lays out the very human and social concerns that accompany such investigations. Lastly, Sample was lucky enough to get an extended interview with Peter Higgs, a shy man who very rarely does interviews. Higgs grew up in Scotland idolizing Paul Dirac and shared Dirac's view of a unifying beauty that would connect nature's disparate facts. In the late 1960s he wrote papers describing what is now called the Higgs boson. The papers were well-accepted in the US and Higgs's name soon began to be bandied about in seminars and meetings. As described below however, Higgs was not the only one postulating the theory.

So what exactly is the Higgs boson? A complete understanding would naturally need a background in theoretical physics, but the best analogy for the layman was given by a British scientist. Imagine a room full of young women who are happily chatting. In walks a handsome young man. As long as he is not noticed he can move freely across the room, but as soon as the young women spot him they cluster around him, impeding his movement. It's as though the young man has become heavier and has acquired mass from the "field" of women surrounding him. The Higgs then is the particle that imparts specific masses to all the other myriad particles discovered so far including quarks and leptons through its own field. It should be evident why it's important. The Higgs would be the crowning achievement in the Standard Model of particle physics which encompasses all particles and forced known until now except gravity.

However, the history of the Higgs particle is complicated. Sample does a great job of explaining why the credit belongs to six different people who reached the same conclusion that Higgs did. It seems that Higgs was not the first to publish, but he was the first one to clearly state the existence of a new particle. However, the most comprehensive theory of the Higgs field and particle came out later. If Nobel Prizes are to be awarded, it's not at all clear what three people should be picked, although Higgs's name seems obvious. The sociology of scientific discovery is as important as the facts and again illustrates that science is a much more haphazard and random process than is believed.

The search for the Higgs gathered tremendous momentum in the 80s and 90s. It intensified after accelerator laboratories spectacularly discovered two particles named the W and Z bosons that are responsible for mediating the electromagnetic and weak interactions (the electroweak force). These particles were predicted by Steven Weinberg, Abdus Salam and Sheldon Glashow in the 60s, and their prediction surely ranks as one of the greatest theoretical successes in modern physics. Once the theory predicted the masses of these particles, they were up for grabs. No experimentalist worth his or her salt would fail to relish nailing a concrete theoretical prediction of fundamental importance through a decisive experiment. Sample captures the pulse-quickening inter-Atlantic races to find these particles especially between CERN and Fermilab. The importance of these particles was so obvious that Nobel Prizes came in quick succession both to the theorists and the experimentalists. However the existence of the Higgs is also essential for the successful formulation of the electroweak theory, and signatures of the Higgs are thought to be produced whenever W and Z bosons are created. It again becomes obvious why finding the Higgs is so important; its existence would validate all those successes and Nobel Prizes, whereas a failure to find it would entail a stunningly hard look at some of particle physics's most fundamental notions.

These days the Large Hadron Collider (LHC) is all over the news. Yet the most exciting part of Sample's book describes not the LHC but the Large Electron Positron collider (LEP) at CERN which was the largest particle accelerator in the world at the time. Unlike protons, electrons and positrons are fundamental particles and crashing them together produces 'cleaner' results. There were some fascinating events associated with the LEP. The behemoth's circumference was 27 kilometers and it crisscrossed the Swiss-French border, so authorities had to seek permission to build the accelerator underneath some homes. It seems that French law is special just like their cheese and language; apparently if you build a house in France, it means that you own the entire ground beneath the house, all the way to the center of the earth. Suffice it to say that some negotiation with the homeowners was necessary to secure permission for underground construction. At one point the intensity of the beams inside the mammoth machine started to wax and wane. After many days of brainstorming a scientist had a hunch; it turns out that the the gravity of the moon and the sun sets up tides inside the crust of the earth. These tides put the calibration of the machine off by a millimeter, too small to be noticed by human beings, but thunderingly large for electron beams. In another case, the daily departure of a train from a nearby station sent surges of electricity into the ground and affected the beams. It seems like when you are building an accelerator you have to guard against the workings of the entire solar system.

The story of particle physics is also fraught with tragedies. One of the biggest described in the book was the construction of the Superconducting Supercollider in Texas. The SSC was supposed to be the answer to CERN and got enthusiastic backing from Reagan and Bush Sr. Unfortunately the budget spiraled out of hand, the infighting intensified, congressmen remained unconvinced and the collider never got built in spite of spending billions and affecting thousands of careers of scientists who had relocated. The fiasco just proved that public support for even projects like the LHC is never a sure thing, and scientists don't always excel at public relations.

Then of course there are all the doomsday scenarios and concerns which were raised about the LHC, from the formation of black holes to the world ending in myriad other ways. As Sample describes, these concerns go back to an accelerator at Brookhaven National Laboratory which would impact large gold ions together at furious velocities. The would-be Nobel laureate Frank Wilczek raised the theoretical yet vanishingly small probability of forming 'strangelets', entities akin to the fictitious substance 'Ice-9' in Kurt Vonnegut's novel 'Cat's Cradle'. These strangelets would coalesce together matter around themselves and form a superstable form of dead matter that would rapidly engulf the entire planet. The concern about strangelets pales in comparison however to the possibility of 'vacuum decay', in which our universe is thought to be in a perfectly happy but metastable state like a vase on a table. All it takes is a little nudge or a massive kick from a high-energy particle collision in our case to dislodge the vase or universe from its metastable state into a stable state of minimum energy. Gratifyingly, not only would this state mean the end of life as we know it but it would also mean the impossibility of life ever arising. Yes, all these scenarios seem straight out of the drug-induced, overactive imagination of a demented mind, but at least some of them are within the realm of theoretical possibility. Unfortunately when the result is the destruction of the planet, the words "improbable" and "vanishingly small" will never do much to assuage the public's fears. It just indicates that physicists will always have to grapple with public relations issues vastly more complex than the LHC.

Finally, we get a fascinating overview of the kinds of things which scientists hope to see in the LHC. The problem is that the generation of particles like the Higgs is a very low-probability event and is usually only a side-product of some other primary event. The situation is made more complicated by the immense difficulty of observing such fleeting glimpses in a hideously complex background of noise generated by the creation of other particles. Scientists working on these projects have to keep their eyes and instruments peeled for the one in a trillion event that may bring them glory. Whenever an event is observed, the scientists have to calculate the realm of probability in which it belongs. Usually if the event is outside five standard deviations ('5 sigma') then it is extremely likely to be real and not have occurred by chance alone. Not surprisingly, the observation and communication of these events is a tortuous thing. Publicity has to be avoided before you confirm such fleeting bits of probability, but leaks inevitably offer. And the media has seldom shown any restraint in announcing such potentially momentous discoveries which would bring glory, prizes and money to their originators. Scientists working today also have to deal with the presence of blogs and other instant communication conduits. As Sample narrates, at least in one case a physicist at CERN posted preliminary LHC results on the blog Cosmic Variance, and all hell broke loose. Scientists have to tread carefully especially in this era of instant data dissemination.

All this makes the scientists engaged in such endeavors live on the edge, and to us they appear like the explorers who have their eyes peeled to the sky looking out for the stray signal that would announce the presence of extraterrestrials. The mathematics of the Higgs boson is of course much more sound than that of alien contact, but the scientists who are looking for it are hanging on to such flimsy wisps of probability and interpretation that they surely must be questioning their own sanity sometimes.

In the end, even physicists are all too human. As Capt. Ramsey says, our rules are not always subject to little devils and angels sitting on our shoulders. And yet it seems that scientists like the Higgs hunters sometimes would be tempted to trust the hairs on the back of their head, especially when those hairs stand up straight at the glimpse of a peak in the graph, that 5-sigma event which would change everything. Maybe, just maybe.

The beat of a different drum

Jagdish Mehra's biography of Feynman, "The Beat of a Different Drum" is one of the more notable biographies of the great man around, with James Gleick's "Genius" being better known to the general public. There is also an excellent biography of Feynman by John and Mary Gribbin. But there seems to be an acrimonious debate in the comments sections of the Amazon reviews of Mehra's book. Essentially they boil down to Neil Mehra, Jagdish Mehra's son, vehemently lambasting anyone who thinks it's not a good biography and who instead happens to praise Gleick's biography.

Mehra cannot stop praising his father enough and constantly noting that he personally knew the greatest physicists of the century including Feynman himself for thirty years. Apparently Feynman used to hold Mehra in very high regard. To be honest, Mehra junior's constant and extreme praise for his father and condescension towards others get a little tiresome after a while, but I have to admit that I remember being fascinated and very impressed with this book when I discovered it in the library of IISc. on a lazy afternoon in the summer of 2002. There are some parts in the book which are full of equations and would be comprehensible only to a theoretical physicist; this thus seems to be the only scientific as well as personal biography of Feynman around as such. Interestingly Silvan Schweber (author of a scientific biography of the men who developed quantum electrodynamics) gave this book a scathing review in Physics Today and berated Mehra for apparently neglecting Gleick's book, and Mehra responded with a clearly angry rejoinder. Mehra noted that the great Hans Bethe (who was one of Feynman's close mentors) had asked Mehra to help Gleick with his Feynman biography.

I of course like Gleick's biography a lot but Mehra junior, notwithstanding his rants, has a point; unlike Mehra who definitely knew Feynman well, Gleick hadn't met the man at all, and I would think this would definitely impact his portrayal of Feynman and make Mehra's portrayal a better one in some respects. Unlike Gleick, Mehra also certainly knew enough physics to actually understand Feynman's work and set it in its correct scientific context. Mehra was also uniquely familiar with the history of physics (and much older than Gleick), edited or wrote several biographies of physicists, and co-authored a magisterial and definitive six-volume conceptual history of quantum mechanics. From a scientific standpoint Mehra was undoubtedly better equipped to understand Feynman's scientific development.

However, a scientific biography is also more than laying out just the science. From what I remember, Gleick was simply the better writer, had a better style and a novelist's eye for detail; consider his fascinating and sparkling narrative in "Chaos". This of course does not make Mehra's biography any less accurate or preempt his understanding of physics and its history but it makes Gleick's book more attractive and accessible to laymen. In the end Mehra was the better physicist and Gleick was the better writer. In any case, this bitter debate has again fueled my desire to read the volume and I have ordered a used copy from Amazon and am eagerly awaiting it.

Is personal acquaintance an important prerequisite for writing a good biography? I think that in general it is, but there also seem to be great counterexamples; Richard Rhodes's famous book for instance does a great job in describing several scientists like Oppenheimer and Bohr who the author had not met. Books like Gleick and Rhodes should encourage young writers to write about historial subjects who they may not have been personally acquainted with.

A BEAUTIFUL, INFORMAL, AND COMPREHENSIVE ACCOUNT OF QUANTUM HISTORY

Uncertainty: Einstein, Heisenberg, Bohr, and the Struggle for the Soul of Science
David Lindley
Anchor, 2008

One of the best informal histories of quantum physics and its makers that I have come across, and I can say I have read many. Concisely and with passionate enthusiasm, Lindley manages to weave together the essential scientific discoveries, the scores of anecdotes about the famous participants including their personal conflicts and friendships, the philosophical and social implications associated with many quantum concepts, and the political and historical turmoil and connections that accompanied these discoveries. While mainly focused on Einstein, Heisenberg and Bohr, Lindley draws vivid portraits of other pioneers such as Pauli, Dirac, Born, Kramers and Schrodinger. Quantum physics is perhaps the most paradoxical, beautiful, bizarre and important scientific paradigm ever developed. The decade from 1920-1930 was undoubtedly the golden era of physics. Lindley succinctly and engagingly tells us how and why. A must read for history of physics lovers.