The main character is Nicholas Salmanovitch Rubashov, a man in his fifties whose character is based on "a number of men who were the victims of the so-called Moscow trials," several of whom "were personally known to the author".[6] Rubashov is a stand-in for the Old Bolsheviks as a group,[7] and Koestler uses him to explore their actions at the 1938 Moscow Show Trials.[8][9]
Secondary characters include some fellow prisoners: