Screwtape writes the letters in C.S. Lewis’s The Screwtape Letters.
Screwtape is an experienced demon who advises his nephew Wormwood on how to tempt a human being known only as “the Patient.” Each letter offers tactical advice about influencing the Patient’s thoughts, habits, relationships, and spiritual life.
Lewis creates the book’s irony by making demonic advice reveal moral truths. Screwtape praises behaviors that damage people and criticizes virtues that help them, so readers are expected to reverse his perspective. The device lets Lewis discuss Christian ethics through satire rather than through a direct sermon.
Wormwood is the recipient, not the author, of the letters. This distinction is the most common source of confusion in questions about the book. The title refers to Screwtape because his voice controls the narrative, even though his nephew’s assignment supplies the correspondence’s immediate context.