The story of the postwar New York intellectuals has been told in a number of histories and autobiographies and even a film, but the saga of their European counterparts, who were on the frontlines of the intellectual battle against communism, has not received as much attention. Perhaps the most intriguing member of this cohort was the journalist and novelist Arthur Koestler (1905–83). A brilliantly talented Hungarian Jew and lapsed communist, he is most famous for Darkness at Noon (1940), the novel that helped explain communism’s powerful hold on intellectuals.

Koestler was born in Budapest to a middle-class Jewish family. After dropping out of the University of Vienna, he linked up with the leader of revisionist Zionism, the charismatic Vladimir Jabotinsky, whom he later called "the first political shaman in my life." He went on to work in Berlin as a journalist for the famous Jewish Ullstein publishing house, until Nazi influence grew and he was forced out. Along the way, he traded his Zionism for communism.

Touring Russia in 1932, Koestler was shaken by what he saw, but he did not summon the courage to break with the party until 1938, when the third and final show trial was conducted in Moscow. The trial of Nikolai Bukharin, a leading Bolshevik, would serve as the basis for episodes in Koestler’s contribution to the anthology The God That Failed (1950). Koestler went on to play a leading role in the battle against communism in the late 1940s, when the Soviet Union enjoyed high moral standing among many Western intellectuals. Measured against that act of courage, the latelife obsession with the paranormal that dismayed so many of Koestler’s admirers seems a mere foible.

Cesarani, director of the Institute of Contemporary History and Weiner Library in London, has a weakness for glib psychological theories (Koestler’s restlessness stemmed from his Jewish ancestry; "guilt was inscribed on his personality"; he was "forever in search of his father"). But the biographer has certainly done the necessary spadework, including extensive digging through archives. There is much to learn here about Koestler’s event-filled life.

—Jacob Heilbrunn