Appointment in Samarra introduces destiny as a theme in its very title, which is taken from an old Mesopotamian tale retold by British author W. Somerset Maugham. In the story, which opens O’Hara’s book as an epigraph, a man tries to avoid Death by escaping Baghdad and heading to Samarra. We later find out that Death is planning on waiting for him in Samarra that night. The tale is about the inevitability of death, and so is Julian’s story. As the narrator discusses Julian’s father, his mother, his wife, and Julian himself, the issue of whether Julian’s fate stems from the congenital traits passed on by his grandfather is brought up repeatedly.

The inevitable and deterministic quality of the protagonist’s death is contrasted with the idea that he is able to control his fate by exercising free will. Each time Julian tries to apologize to Harry, when he attempts to clear the air by talking to Monsignor Creedon and when he asks Caroline to run away with him, he is attempting to prevent his own self-destruction. However, the amount of willpower he is able to exert tends to fall short.

There’s a certain amount of chance surrounding the events in the story. The book emphasizes the importance of chance by giving a detailed account of events as they happen simultaneously and consecutively within Julian’s inner and outer circles, as if they were pieces in a puzzle. Whether these should be seen as pieces of chance in a random puzzle or as acts of fate in a predetermined pattern is left up to the reader.