National Library Week is a time to celebrate the most influential books in literary history. But not every novel that's considered a classic today received instant praise. Many beloved titles had to overcome years of censorship before securing spots on required reading lists and library shelves.

The American Library Association has shared a list of books from the Radcliffe Publishing Course Top 100 Novels of the 20th Century that have been challenged or banned. Of the 100 books, nearly half have received pushback from institutions in the past. Some have been criticized for featuring violence (Beloved), profanity (To Kill a Mockingbird), or controversial political messages (Animal Farm). Even seemingly inoffensive novels have been targeted by censors. (The Lord of the Rings was burned outside a New Mexico church in 2001 for being "satanic.")

Below are 25 of the most popular works of literature from the last century that have been banned from schools, libraries, and, in some cases, entire countries. For even more great books that have been banned, including picture books like Dr. Seuss's The Lorax, check out this list.

  1. The Catcher in the Rye by J.D. Salinger

  1. The Grapes of Wrath by John Steinbeck

  1. To Kill a Mockingbird by Harper Lee

  1. The Color Purple by Alice Walker

  1. Beloved by Toni Morrison

  1. Gone With the Wind by Margaret Mitchell

  1. Lolita by Vladimir Nabokov

  1. Of Mice and Men by John Steinbeck

  1. Catch-22 by Joseph Heller

  1. Brave New World by Aldous Huxley

  1. Animal Farm by George Orwell

  1. The Sun Also Rises by Ernest Hemingway

  1. As I Lay Dying by William Faulkner

  1. A Farewell to Arms by Ernest Hemingway

  1. Invisible Man by Ralph Ellison

  1. Native Son by Richard Wright

  1. One Flew Over the Cuckoo's Nest by Ken Kesey

  1. Slaughterhouse Five by Kurt Vonnegut

  1. For Whom the Bell Tolls by Ernest Hemingway

  1. The Call of the Wild by Jack London

  1. The Jungle by Upton Sinclair

  1. Lady Chatterley's Lover by D.H. Lawrence

  1. A Clockwork Orange by Anthony Burgess

  1. The Awakening by Kate Chopin

  1. In Cold Blood by Truman Capote