What is the role of the epigraph in The Tell-Tale Heart?

In "The Tell-Tale Heart," the epigraph serves to establish the story's themes of madness and guilt. It hints at the narrator's unstable mental state and foreshadows the tension that unfolds throughout the tale. By framing the narrative with this insight, the epigraph invites readers to question the reliability of the narrator and sets the tone for the exploration of psychological turmoil. Ultimately, it underscores the story's exploration of the thin line between sanity and insanity.