"The American Library Association promotes the freedom to choose or the freedom to express one's opinions even if that opinion might be considered unorthodox or unpopular, and stresses the importance of ensuring the availability of those viewpoints to all who wish to read them."
Difference between a challenged & banned book" http://www.ala.org/bbooks/about
Annual List of ALA Banned & Challenged Books
The links to list of books challenged, restricted, removed, or banned each as reported in the Newsletter on Intellectual Freedom are below. Some links download a PDF of each list while others link to a web page.