UnSuggester is a book recommendation engine in reverse; enter a book you liked, and it'll give you a list of books you probably won't like. Apparently, fans of
William Gibson's Neuromancer and
Michael Moore's Stupid White Men would least want to read books on theology, the opposites of
Marx & Engels' Communist Manifesto look like erotica novels, Bulgakov's
The Master and Margarita is the least like an array of romance novels, Star Wars novelisations and theological texts, and the opposites of
Design Patterns are mostly chick-lit, whereas
The Little Prince finds itself to be the antithesis of thrillers and scifi novels. Meanwhile, people who read
Illuminatus! are unlikely to read
Freakonomics, and the opposite of
The Da Vinci Code, with its simplistic structure and grand revelations, appears to be, naturally enough, French postmodernist philosophy.
I've read about half of those - and I'd recommend Illuminatus! to anyone who enjoyed Freakonomics and visa versa.