Hannah Baker is a fictional character from the novel and Netflix series titled "13 Reasons Why." She is a high school student who faces various challenges, including bullying, mental health issues, and struggles with relationships. Her story is told through a series of cassette tapes she leaves behind after her tragic death, detailing the reasons that led her to take her own life. The narrative explores themes of teenage struggles, mental health, and the impact of bullying. Hannah's experiences highlight the importance of communication and understanding among peers, as well as the need for support systems in schools and communities.