One of the best examples of an unreliable narrator is Patrick Bateman, narrator of Bret Easton Ellis's 1991 novel "American Psycho." Bateman describes numerous horrifying acts throughout the novel, but they may all just be figments of his imagination.
The term "unreliable narrator" was first introduced by literary scholar Wayne C. Booth in his 1961 book "The Rhetoric of Fiction." The term refers to a narrator who, whether intentionally or unintentionally, presents deceptive information to readers and cannot be trusted to tell the truth. Patrick Bateman spends most of the novel detailing horrifying murders and acts of violence, but the reader may recognize these as delusions meant to comment on the violent nature of modern society.