Koestler was a man of enormous talent, particularly as a journalist, but also of vast psychological complexity. He could see into things with a clarity that stirred not just the mind but the deepest emotions. Yet he was emotionally twisted and even toxic in close relationships. The man who takes shape in Cesarani's biography is a remarkably engrossing figure, living the first half of his life on the edge and the last half beyond the pale -- or so he was seen after he made his commitment to parapsychology and parascience later in life. He got to Darkness at Noon, his terrifying 1940 portrait of Stalinism, not through study but through quest. This emotional and intellectual journey led first to a radical anti-Marxist Zionism, then to membership in the German Communist Party and pilgrimage to the Soviet Union, later to near execution in the Spanish Civil War, and finally to defection from communism. All this was but a prelude to still more harrowing adventures. Readers, mouths agape, may at times see a kind of politicized Indiana Jones, but Cesarani continually yanks them back to the intellectual and human stakes involved.