The Perfect Stranger, the book within the novel, is a multifaceted symbol that stands for opposing things for the two main characters. For Catherine, the book—though its narrative is untrue—represents the threat of exposure for a secret she has been keeping for 20 years. Before Catherine forces herself to read the book in its entirety, its mere presence in her house produces immense paranoia and feelings of danger. Catherine doesn’t even want to look at the book, because this association is so strong. She tries to cover the book up with a newspaper when Robert is around, and when he is asleep, she tries to burn the book and rid the house of its threat. These actions reflect Catherine’s desire to keep her trauma hidden from her family, which the book’s existence jeopardizes.

On the other hand, for Stephen, the book is a symbolic weapon of justice. Stephen assumes that Catherine is to blame for Jonathan’s death, so he uses the book to force her into accountability. Stephen sees the book as “a little grenade waiting for someone to pull the pin” (63). He hopes its story will inflict as much damage on Catherine as possible. When Catherine doesn’t respond as apologetically as he hopes, Stephen further weaponizes the book by sending copies to Nicholas, Robert, and Catherine’s workplace, hoping to torment Catherine by ruining her relationships and reputation.