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.