Running Google search for news articles is also a good way to find information on banned books. 

Some keywords include: banned, challenged, controversy, censorship. You can combine one or more of these keywords into your search, along with the title of the book you are interested. 

Example: If I combine "Game of Thrones" plus the word "banned" and "book" into Google:  

I will get results about how the books is currently banned in U.S. prisons. (I put the word "book" into the search to differentiate my search from similar banning efforts currently underway with the popular HBO TV series). This not only helps to show if a book is / was controversial, it's also an excellent way to identify supporting sources for your research. 

Getting there: https://library.fullcoll.edu/  Type a keyword or two into the search box below for a basic search.  But if you would like to try an ADVANCED search, simply hit search (blank), then click on the Advanced Search link on the next screen.

Use the databases to research topics relevant to banned books. Some keywords that can yield many results include: censorship, "freedom to read," "banned books,"