Tredici by Jay Asher

A teenage boy receives a box of cassette tapes recorded by a classmate who recently took her own life; each tape names a person and recounts incidents—some small, some cruel—that she says contributed to her despair, and as he listens he confronts guilt, complicity, and the ripple effects of bullying, secrets, and indifference while piecing together how a series of ordinary choices and betrayals led to a tragic outcome.