Ludwig Wittgenstein possessed one of the most acute philosophical minds of the twentieth century. In this incisive portrait, Ray Monk offers a unique insight into the life and work of a modern genius. Wittgenstein was a tortured man who fought his calling in philosophy and never fully came to terms with his gifts. A reluctant Cambridge don, he was uncomfortable in the university setting and believed that a professor could not be an authentic philosopher. In friendship and in love, he was attracted to gentle, intelligent younger men, yet he was so troubled by his own sensuality that these attachments existed mostly in his imagination. Based on previously unpublished Wittgenstein letters and writings, this richly textured biography reveals the connection between the tormented private man and the genius who, in the epoch-making works 'Tractatus Logico-Philosophicus' and 'Philosophical Investigations', radically redirected philosophical thought in our time.