Illustration of the French author and poet Voltaire (1694-1778). Born Francois Marie Arouet, Voltaire wrote more than 20,000 letters and more than 2000 books and pamphlets. Among his scientific works was Elemens de la Philosophie de Newton (1738), a guide to the theories of Isaac Newton. Voltaire also wrote on history, philosophy, religion and politics. He was a fierce critic of social and political injustices, which led to several periods of exile or imprisonment. Over a decade after his death, the French authorities honoured him with a ceremonial re-burial in the Pantheon, Paris, in 1791. Illustration from 1864.