This thesis analyzes the popularity and success of the first four Harry Potter books by J.K. Rowling. It examines their publication history, marketing strategies, and how they draw from different literary genres like the school story, epic/romance, and modern fantasy. The thesis argues that Rowling's unique blending of these genres through her use of morality and values contributes to the books' complexity and widespread appeal to both children and adults. It aims to understand why the Harry Potter series has become such a global phenomenon.