1. The books in the Harry Potter series by J.K. Rowling were the most challenged ones from 2000–2009.
2. From 2000–2009, the biggest reasons books were banned was because they were "sexually explicit" and had "offensive language."
3. In June, John Green's Paper Towns was challenged and taken off of library shelves in a Florida middle school.
4. Lawrence Ferlinghetti was arrested and went to trial as the publisher of Allen Ginsberg's "Howl" because the poem features "homosexual acts." Ferlinghetti ultimately won the case.
5. A community in Arkansas voted to put restrictions on Harry Potter books in the Cedarville School District but was overturned in 2003 by federal courts.
6. Last year, Eleanor & Park by Rainbow Rowell was challenged by a Minnesota school board because of the author's "profanity" and "sexual content."
7. Seven books were successfully banned from the Highland Park Independent School District in Texas a couple of weeks ago: Song of Solomon, An Abundance of Katherines, The Art of Racing in the Rain, Siddhartha, The Working Poor: Invisible in America, The Absolutely True Diary of a Part-Time Indian, and The Glass Castle: A Memoir.
8. The most challenged book from 2001–2013 is the Captain Underpants series by Dav Pilkey.
9. From 1990–1999, Judy Blume was one of the most challenged authors, with five books on the most frequently challenged list: Forever, Blubber, Deenie, Are You There, God? It's Me, Margaret, and Tiger Eyes.
10. Maya Angelou's I Know Why the Caged Bird Sings is one of the most challenged books of all time, citing "racism, homosexuality, sexually explicit, offensive language, unsuited to age group."
11. In 2013, a North Carolina school district decided in a 5-2 vote to ban Invisible Man by Ralph Ellison after a parent complaint. Nine days later, the school board voted again and reversed its initial decision due to backlash from the larger community.
12. Just this past August, a minister in Cleveland, Texas, started a petition to remove books about "vampires in relationships with young teens" (like Twilight by Stephanie Meyer and the House of Night series by P.C. Cast and Kristin Cast) from a local library.
13. Parents in Oregon are currently trying to ban Persepolis by Marjane Satrapi from their high school libraries.
14. The Absolutely True Diary of a Part-Time Indian by Sherman Alexie was banned from a school district in Idaho. This month, the book was reinstated again but with restrictions.
15. In 1960, one Oklahoma teacher was fired for assigning The Catcher in the Rye by J.D. Salinger to an 11th-grade English class.
16. The Giver by Lois Lowry was the 11th-most frequently challenged book from 1990–1999.
17. John Green, Toni Morrison, Suzanne Collins, and Stephen Chbosky are among the most frequently challenged authors since 2013.
18. Margaret Atwood's The Handmaid's Tale was banned from a Texas high school in 2006 when a parent complained it was "sexually explicit and offensive to Christians." The decision was ultimately overturned.
19. To Kill a Mockingbird by Harper Lee has been challenged for the past seven decades, the same amount of time it's been in publication.
20. In April 2013, parents challenged Anne Frank's classic Diary of Young Girl in a Michigan middle school because of its "pornographic passages."
21. Last month, parents in Wisconsin requested that The Kite Runner by Khaled Hosseini and Chinese Handcuffs by Chris Crutcher be removed from their local school system, but their complain was denied. They're currently appealing the decision.
22. Books are most likely to be challenged and restricted because of concerns from parents.