Banned Book Week is an annual event held during the last week in September to celebrate the freedom of reading.

It was first launched in 1982 in response to a spike in the number of challenges to books in schools, bookstores and libraries. According to the American Library Association, more than 11,300 books have been challenged by parents, patrons and school administrators since then.

The ALA’s Office for Intellectual Freedom complies a list of the top ten most frequently challenged books. In 2013, 307 challenged books were received by a formal written complaint requesting that materials be removed because of content. Through the efforts of libraries, teachers and communities, many efforts to ban challenged books are unsuccessful.

Here is a list of the top ten challenged books for 2013:

1. “Captain Underpants” (series) by Dav Pilkey. This marks the series’ fifth appearance on the list for: offensive language, unsuited for age group, violence.

Summary: The series follows two fourth grade boys and their comic book creation, Captain Underpants in adventures within their school that discourages imagination and fun.

2. “The Bluest Eye” by Toni Morrison. Challenged for: offensive language, sexually explicit, unsuited to age group and violence.

Summary: The story is set in the Midwest during the Great Depression and follows a young girl who develops an inferiority complex due to her skin color.

3. “The Absolutely True Diary of a Part-Time Indian” by Sherman Alexie. This book is on the list for the fourth consecutive year: drugs/alcohol/smoking, offensive language, racism, sexually explicit and unsuited to age group.

Summary: Arnold, a medically challenged Native American is sent to school off of the reservation and deals with the challenges of being a fish-out-of-water and family tragedies.

4. “Fifty Shades of Grey” by E.L. James. The book’s second appearance in a row to being challenged in schools due to: nudity, offensive language, religious viewpoints, sexually explicit and unsuited to age group.

Summary: College student Ana meets young business entrepreneur/bondage aficionado Christian Grey and embark in a passionate love affair.

5. “The Hunger Games” (series) by Suzanne Collins. Reasons given: religious viewpoints and unsuited to age group.

Summary: The series follows Katniss Everdeen in a dystopian future where kids are sent to battle for their lives in a reality show to keep the peace and her rebelliousness eventually starts a revolution against the Capitol.

6. “A Bad Boy Can Be Good for A Girl” by Tanya Lee Stone. On the list for the first time for: drugs/alcohol/smoking, nudity, offensive language and sexually explicit.

Summary: This story follows three high school girls who fall in love with the same boy.

7. “Looking for Alaska” by John Green. On the list a second time for: drugs/alcohol/smoking, sexually explicit and unsuited to age group.

Summary: The book follows a group of friends at a prep school that deal with guilt of a friend’s death.

8. “The Perks of Being a Wallflower” by Stephen Chobsky. The sixth appearance for: drugs/alcohol/smoking, homosexuality, sexually explicit and unsuited to age group.

Summary: The book follows intellectual yet socially awkward Charlie during his first year of high school.

9. “Bless Me, Ultima” by Rudolfo Anaya. The second appearance for: occult/Satanism, offensive language, religious viewpoint and sexually explicit.

Summary: It’s a semi-autobiographical coming of age story set in a small New Mexican town.

10. “Bone” (series) by Jeff Smith. A first appearance for: political viewpoint, racism and violence.

Summary: comic book series following the adventures of cousins Fone, Smiley and Phoney Bone.