The strap Mark Callender was hanged with is the most important symbol in this text. The knot tied into the strap confirms that Mark was murdered, as he could not have created that knot himself. The different knot used to hang the pillow tells Cordelia that it is not the murderer who is trying to scare her. The belt is also a “talisman” for Cordelia, and it saves her life when she is trapped in the well. The belt further symbolizes the theme of duality: It can bring death and give life.

Throughout the novel what is outside is contrasted against what is inside. Sir Ronald is a respected scientist and peer; he is also a murderer. Cordelia is a pretty young woman; she is also a ruthlessly intelligent and resourceful detective. Bernie was a hack; he also trained Cordelia to be an even match for Dalgliesh. Isabelle is vapidly beautiful; she also has a keen eye for fine art. Amid these contradictions Mark exists as an enigma, revealed only through the way others describe him, which suggests that appearances are reality.