Jean-Paul Sartre must be the first philosopher to have created his own industry. Witness the rush of bestselling pocket guides to existentialism in the forties, the scoops for Ce Soir on Sartre’s latest amorous adventures and of course the biographies, of which Annie Cohen-Solal’s will probably be the most widely read in France, where this vast book has already made her a celebrity.

It is not a critical biography, in either political, philosophical or literary terms. It is, however, the most exhaustive and exhausting biography so far, written at a time when the American instigator of the project could not find any French publisher to underwrite a life of Sartre. The public having its famously short memory, Sartre’s undeniable status as one of the greatest intellectual leaders of the century was in eclipse, only seven years after a crowd of 50,000 followed the cortege to his funeral. So part of Cohen-Solal’s Herculean labour is to remind us how he achieved that status by recreating this highly complicated life. She veers neither towards hagiography nor towards corrective detraction, and skilfully encompasses the wash of evidence from thousands of people, books, letters, diaries, newspapers, even the FBI archives, as well as the massive autobiographical record he himself left. Her only reference to the scale of the task is an uncomplaining suggestion that Sartre would make any biographer sweat blood.

Cohen-Solal is not an evocative writer. You might find the odd flourish of touristic colour in a cafe scene, but she is not concerned with atmosphere, either domestic or global, and deals in hard fact, direct quotations and wholesale newscuttings. International events are rapidly despatched, as though the context for