Unlike the other contributors to this book, I have never made an extended study of the life of a single individual. Rather, I have approached biography as a way to comprehend history, to understand movements and currents of thought by examining the lives of individuals who contributed to them. As a result, my intellectual and psychological involvement may be somewhat different from that of the typical biographer. The experience of steeping oneself in the concerns, aspirations, and feelings of a single figure over an extended period is not one that I have shared. Indeed, except for my work on Leo Tolstoi, I have avoided major figures, seeking the typical rather than the outstanding and examining dominant and widespread responses rather than the original visions of a genius.