The Critique of Dialectical Reason was first published in France twenty years ago, in 1960. The book, we know from Simone de Beauvoir, was flung together in a hurry, written virtually without correction during the height of the Algerian war, a period, for Sartre, of stress and anxious stock-taking of his position as a Marxist and a long-term non-joiner of the Communist Party. The whole sense in which, in 1960, Sartre was a Marxist, the question of precisely how eccentric his kind of Marxism was, is centred on his theory of historical explanation. I do not propose to raise many detailed questions about the relation of Sartre's views on history to those of Marx himself, still less to those of other Marxists. Ignorance alone would rule out such a course. I would like if I can, however, to consider Sartre's own view of historical explanation as it appears in the Critique, and leave it to others if they wish to fit it into the Marxist tradition, or exclude it. In order to perform this relatively modest expository task, it will be necessary for me to refer, from time to time, to Sartre's earlier philosophical views. But this will come in incidentally