The story that is told in Lord Russell's recent book My Philosophical Development (Allen and Unwin, 18s.) is one that has been told before, by him and by others, but this particular presentation of it stands out by reason of its comprehensiveness and its authority. It is a rather austerely intellectual autobiography, sticking firmly to the topic announced in its title, and the non-philosophical aspects of the author's character and interests take as modest a place in it as Collingwood's do in his not altogether dissimilar Autobiography. What makes a comparison of these two intellectual self-portraits so tempting is the almost diametrical opposition of their authors. Russell is an aristocrat, an influential public figure too lively and multifarious to be contained for long in a university, a communicator who writes to be understood and believed, a mathematician still despite many years away from mathematics, a moral and political radical, an atheist and a lifelong defender of science as the most solid and enduring achievement of the human intellept. Collingwood was a scholarship boy, the son of an unsuccessful literary man, a pure example of the obscure and ineffectual don, who made out that he was too busy to answer criticism or to take part in college administration or university politics, an elaborately conscious stylist, almost as much a historian and an archaeologist as he was a philosopher, essentially a reactionary for all his autumnal flirtation with Marxism, a Christian (up to a point) and an embattled critic of the pretensions of science.