Andrew S. Curran recounts the only meeting between the two great philosophes Denis Diderot and Voltaire early in 1778 when Diderot, aged sixty-five, insulted Voltaire, then eighty-five, by averring that contemporary playwrights (including, by implication, the two of them) would not brush Shakespeare’s testicles if they walked between his legs. Two months later, Voltaire was dead; a few weeks later, Jean-Jacques Rousseau also died, aged sixty-six. Diderot – regarded by many as the greatest of the three – lived a little longer, until 1784. The last words his daughter Marie-Angélique heard him say were ‘the first step towards philosophy is incredulity’.

Diderot was born in 1713 into a family of master cutlers in the fortified hilltop town of Langres, north of Dijon in eastern France. Originally destined for a clerical career, he dismayed his respectable parents by turning his back on the church and then, after studies in Paris, on religion altogether. He lived a life of prodigiously creative brilliance, captured here with verve and deep erudition by Curran.