Arthur Koestler (1905-1983), a Hungarian-British author and journalist, was deeply involved in the great ideological and social disputes of his era. In 1931, Koestler joined the German Communist Party, which he left in 1938 after becoming disillusioned with Stalinism. He garnered international acclaim for his anti-totalitarian novel Darkness at Noon, which he published in 1940. Koestler advocated for a variety of political causes throughout his life. His novels, reporting, autobiographies, and political and cultural essays positioned him as a key commentator on the twentieth-century's difficulties.