Thirteen Reasons Why by Jay Asher

Thirteen Reasons Why, also known spelled as Th1rteen R3asons Why, is a 2007 New York Times best-selling young-adult fiction novel written by Jay Asher: Clay Jensen, a somewhat shy high school student, returns home from school one day to find an anonymously-sent package sitting on his doorstep. Upon opening it, he discovers that it is a shoebox containing seven cassette tapes recorded by the late Hannah Baker, his classmate and emotional crush who recently committed suicide. The tapes were initially mailed to one classmate with instructions to pass them from one student to another, in the style of a chain letter. On the tapes, Hannah explains to thirteen people how they played a role in her death, by giving thirteen reasons to explain why she took her life.
Hannah has given a second set of tapes to one of their classmates, the identity of whom Clay later discovers, and warns the people on the tapes that if they do not pass them on, the second set will be leaked to the entire student body. This could lead to the public embarrassment and shame of certain people, while others could face physical harassment charges or jail time. Through the audio narrative, Hannah reveals her pain and suffering and the slide into depression that ultimately leads to her death (suicide from pills). She lists her first crush, a boy who voted her "best ass in the freshman class", a former friend, a peeping Tom, a liar, a goof who takes advantage of her, a hater, a thief who steals her poems, a member of the list that already passed, a cheerleader who crashes into a stop sign, a guy who raped her in a hot tub... (Summary by Wikipedia)