An unreliable narrator is a storyteller whose credibility is compromised, leading readers to question the truth of their account. This can occur due to personal biases, mental instability, or intentional deceit. The narrator's perspective may distort the events, making it challenging for the audience to discern reality from fiction. In literature, examples of unreliable narrators include characters like Holden Caulfield from The Catcher in the Rye and Patrick Bateman from American Psycho. These narrators provide a skewed view of their experiences, prompting readers to engage critically with the text and uncover the underlying truths.