Harry Potter series — J.K. Rowling

The Harry Potter series holds the record as the most challenged book series in American libraries during the 2000s, drawing over 500 formal complaints to the American Library Association. The primary grounds for challenges include allegations of promoting witchcraft, the occult, and anti-Christian values. Notably, these complaints outnumber those of the #10-ranked *The Diary of a Young Girl* by more than 500:1 in pure volume, despite the series dominating global sales at 500 million copies. This paradox—a series being both the most widely read fiction of the decade and the most challenged—reveals how bans operate alongside mainstream acceptance. The majority of challenges originated from religious conservative groups targeting the magical themes, even as over 70% of American parents surveyed by Pew Research Center in 2019 supported their children reading the books. Thus, while complaints surged, readership remained unabated.