This was the third novel of Arthur Koestler's trilogy on ends and means - the other two are THE GLADIATORS and DARKNESS AT NOON - and the first he wrote in English. The central theme is the conflict between morality and expediency, and in this novel Koestler worked it out in terms of individual psychology. Peter Slavek starts out as a brave young revolutionary, but suffers a breakdown. On the analyst's couch he is made to discover, in Koestler's own words, 'that his crusading zeal was derived from unconscious guilt'.