The American Library Association (ALA) offers lists of banned and challenged books... those books which individuals and/or groups have sought to have removed from school curricula and/or from collections at public libraries.

Wikipedia has a summary article with a List of most commonly challenged books in the United States and links to ALA resources from which much of the article was derived.

Gifted children may be interested in the thought-provoking content of some of these books; Parents may wish to pre-screen.

One title of interest may be The Giver as the memories, "seeing beyond", and deep understanding developed by the character Jonas may in some ways parallel the gifted experience... and the resultant social rift between the gifted and typical age-mates, who simply do not share the knowledge base and therefore may be unable to relate to certain experiences and/or viewpoints.