The Moscow trials form the pivot around which this interpretation of the spirit and logic of the Russian Revolution is built. As an interpretation it is brilliantly handled; as a novel it is almost motionless; it appeals more as an exercise in revolutionary ratiocination. Koestler, who knew several of the actual figures in the trials, has chosen a fictional Rubashov to embody the characteristics and activities of those involved. Through the period of his prison stay, we see the mentality of the revolutionist in his intellectual self-debates as he approaches a period of doubt, questioning whether the end justifies the means, whether the idea of mankind is more valid than the idea of man. For this breach of faith he is executed. Many serious studies have been made of the trials; this novel comes as near the sense of truth as any of them. The market, however, is limited.