Nearly any book by Smullyan is likely to be enjoyable to LW readers, if not particularly on-topic for Less Wrong.

• What is the Name of this Book? is classic - this is the canonical source (maybe the original source, I'm not sure) of the liars/truth-tellers puzzles and other delights.
• "To Mock a Mockingbird" is a nicely-paced set of puzzles that just happens to lead the reader through the first few key insights of combinatory logic.
• "The Tao is Silent" is what happens when you soak a brilliant logician in Taoism for a while. Somewhat in this flavor is his story Planet Without Laughter, which is the best defense of something between mysticism and realism I've met.