Arthur Koestler (kĕst´lər), 1905–83, English writer, b. Budapest of Hungarian parents. Koestler spent his early years in Vienna and Palestine. He was an influential Communist journalist in Berlin in the early 1930s, traveled through the Soviet Union, and moved to Paris. Later, as a correspondent for a British newspaper, he was captured and imprisoned by Franco's forces during the Spanish Civil War; Spanish Testament (1937) and Dialogue with Death (1942) relate his experiences. Released in 1937, he edited an anti-Nazi and anti-Soviet French weekly and served in the French Foreign Legion (1939–40). After the German invasion he was interned in a concentration camp, but escaped from France in 1940 and lived thereafter in England and the United States, continuing to travel widely after the war. By 1940 Koestler had broken with Communism, largely as a result of the Soviet purge trials of the late 1930s and the Hitler-Stalin nonaggression pact of 1939. The anti-Communist Darkness at Noon (1941), his most important and best-selling novel, vividly describes the imprisonment, interrogation, and execution of an old Bolshevik in a Communist prison for his
belief in the individual. Koestler's other significant accounts of the evils of Stalinism include The Yogi and the Commissar (1945), and the essay he contributed to The God That Failed (ed. by R. H. Crossman, 1951).
Koestler's later writings ranged over a wide variety of subjects. His later novels include Thieves in the Night (1946), a powerful description of the conflict between Arabs and Jews in Palestine, The Age of Longing (1951), and The Call Girls: A Tragicomedy (1973). He wrote extensively on science in such works as The Lotus and the Robot (1960), The Act of Creation (1964), The Ghost in the Machine (1968), The Case of the Midwife Toad (1971), and The Roots of Coincidence (1972). Greatly concerned in later life with euthanasia and the right to die, an ailing Koestler and his healthy wife committed joint suicide in 1983. The author of more than 30 books and hundreds of articles, Koestler combined a brilliant journalistic style with an understanding of the great movements of his times and a participant's sense of commitment.
See his autobiographies, Scum of the Earth (1941), Arrow in the Blue (1952), The Invisible Writing (1954), and Janus: A Summing Up (1978); biographies by I. Hamilton (1982), D. Cesarani (1999), and M. Scammell (2009); studies by W. Mays (1973), S. Pearson (1978), and P. J. Keane (1980).