Harry Potter and the Philosopher's Stone - JK Rowling
In the US these books changed the focus of censorship in schools and libraries. Before 1999, challenges were to do with sex, the human body or “inappropriate” language. This shifted to focus on the fantasy and glorification of magic and the occult, which confused children and tempted them to try the spells and curses they read about.
There were concerns over the violence and increasingly dark tone of the later books but most of the censorship attempts were for religious reasons. It was also banned in some Christian schools in the UK.