Biography has often been described in not entirely flattering terms. Its practitioners have been likened to vultures and parasites by those who feel that they or those they admire have been unfairly treated. Few biographers, however, would cast themselves in the role of vandals and grave robbers, as Andrew Curran does in the prologue to Diderot and the Art of Thinking Freely. It begins with a vivid reconstruction of the devastation in 1793 of what was supposed to be Denis Diderot’s last resting place in the Eglise Saint-Roch in Paris. Curran skilfully evokes the moment when thieves, who had broken into the church not out of revolutionary fervour but in search of copper and lead to sell, prised open the ossuary and tipped assorted skeletons out of their lead coffins, leaving behind a heap of bones, some of which had belonged to Diderot, who had died nearly ten years earlier.