Lying, per se, isn't illegal. If it was, most politicians and salespeople would never get out of jail.
If the book is still in copyright, and your wiki has any direct quotes from the book (or text that you claim is direct quotes, even though it isn't), that could be copyright infringement.
If the author is still alive, and feels that your wiki harms his reputation, he might sue you for libel. Though I don't think I've ever heard of an author suing someone for writing a review of his book (which is essentially what your wiki would be), even if the review contains blatant lies. If your wiki is specific enough to say something like, "In book X, author Y states Z" then anyone who cares can read book X and see that it says nothing of the sort. In other words, the only person who would think that Y said Z is someone who doesn't care enough to see for themselves or someone who's already inclined to believe that Z is the sort of thing that Y would say. So it's hard to see how you could harm Y's reputation enough to justify his suing you.
If your wiki isn't an act of copyright infringement or libel, all you're left with is that you'll look like a chump when someone calls you on it.