The American Library Association says the number of reported challenges in the past 30 years has hovered between about 400 or 500 , but there are many bans they never learn about. While parents have traditionally launched the lion’s share of challenges, Deborah Caldwell-Stone, an attorney with the association, says she has noticed “an uptick in organized efforts ” to remove books from public and school libraries.The library association reports that this year alone, U.S. schools have banned more than 20 books and faced more than 50 other challenges, with many more expected this fall as school starts.A review of the books banned by various schools in the past six months illustrates that eliminating this “objectionable material” actually deprives students of the chance to think and form their own opinions about difficult questions.List of books banned: