Here's why it's still very famous:
* Critical and commercial success: It was a major bestseller upon release and received positive critical reviews.
* Key plot developments: The book introduces crucial characters like Sirius Black and Dolores Umbridge, and features the return of Voldemort and the beginning of the war.
* Adaptations: It was adapted into a major motion picture, which further cemented its place in popular culture.
While it might not be as universally known as the first book, Harry Potter and the Order of the Phoenix remains a significant entry in the series and a beloved story for many fans.