Harry Potter And The Prisoner Of Azkaban by J. K Rowling

In this third installment of the popular fantasy series, the protagonist enters his third year at a magical school, only to find out that a notorious prisoner has escaped from a supposedly inescapable prison and is believed to be after him. As the school year progresses, he learns more about his parents' history, uncovers secrets about his professor, and discovers a magical map. He also learns to summon a powerful defensive spell, confronts the escaped prisoner, and uncovers the truth about his parents' betrayal and death. The book ends with him saving an innocent life and learning a valuable lesson about the complexity of human nature and the importance of true friendship.

The 284th greatest book of all time