<p>Best known as the author of the classic <i>Darkness at Noon</i>, Koestler was one of the most influential and controversial intellectuals, involved in and commenting on almost every political movement of the twentieth century. As young man, he was a committed Zionist and moved to Palestine; he was imprisoned and sentenced to death in Franco''s Spain; escaped Occupied France; and was a member of the Communist party for seven years, later becoming one of its fiercest critics with the publication of <i>Darkness at Noon</i>. <br><br>Without sentimentality, Scammell gives a full account of Koestler''s turbulent private life: his drug use, manic depression, the frenetic womanizing that doomed his three marriages and led to an accusation of rape, and his startling suicide pact with his wife in 1983.<i> Koestler</i> also gives a full account of the author''s voluminous writings, making the case that the autobiographies and essays are fit to stand beside <i>Darkness at Noon</i> as works of l