Actually this tool seems to solve that problem by showing you multiple books, and not just direct opposites in terms of content. If you don't believe me search

Actually this tool seems to solve that problem by showing you multiple books, and not just direct opposites in terms of content. If you don't believe me search for 'Mein Kampf' and something similar, it doesn't spit out books you would consider opponents of Hitler's worldview necessarily. Now whether the books it spits out are even going to help you break out of your worldview, who knows, but I'm sure reading Shakespeare is going to loosen up a fascist to other ideas at least a little bit.