Darkness at Noon (German: Sonnenfinsternis, lit. 'Solar eclipse') is a novel by Austrian-Hungarian-born novelist Arthur Koestler, first published in 1940. His best known work, it is the tale of Rubashov, an Old Bolshevik who is arrested, imprisoned, and tried for treason against the government that he had helped to create.
The novel is set between 1938 and 1940, after the Great Purge and Moscow show trials. Despite being based on real events, the novel does not name either Russia or the Soviets, and tends to use generic terms to describe people and organizations; for example, the Soviet government is referred to as "the Party" and Nazi Germany is referred to as "the Dictatorship". Joseph Stalin is represented by "Number One", a menacing dictator. The novel expresses the author's disillusionment with Bolshevism, Stalinism, and the ideology of the Communist Party of the Soviet Union at the outset of World War II.