Symbolic Logic and the Game of Logic (Dover Recreational Math)
Yes, this is the Lewis Carroll who wroteAlice in Wonderland, and these two works show the same quirky humor. Here you see Carroll the mathematician at his playful best. Don't let the title of the first work mislead you--this isn't about modern symbolic logic but about ways of expressing classical logic with symbols. It's loaded with amusing problems to delight any mathematical puzzler. In the second work he turns logic into a game played with diagrams and colored counters, giving you hundreds of challenging and witty syllogisms to solve. Great mind-stretching fun.