The Darkroom of Damocles by Willem Frederik Hermans
During the German occupation of Holland, tobacconist Henri Osewoudt finds himself drawn into the resistance when he is visited by the ruthless Dorbeck, who also happens to look remarkably like him. Soon Osewoudt is carrying out dangerous missions, helping British agents and killing collaborators with aplomb. But after the war, he is taken for a collaborator himself. How can he prove that he was on the right side - and how much of what he remembers is real? The Darkroom of Damocles is a razor-sharp thriller set in a world where everything is permitted, even murder. As unsettling and morally challenging today as when it was first written.