Boris Kuznetsov was a scientist among humanists, a philosopher among scientists, a historian for those who look to the future, an optimist in an age of sadness. He was steeped in classical European culture, from earliest times to the latest avant-garde, and he roamed through the ages, an inveterate time-traveller, chatting and arguing with Aristotle and Descartes, Heine and Dante, among many others. Kuznetsov was also, in his intelligent and thoughtful way, a Marxist scholar and a practical engineer, a patriotic Russian Jew of the first sixty years of the Soviet Union. Above all he meditated...