Good Book On Combinatorics What is your recommendation for an in-depth introductory combinatoric book? A book that doesn't just tell you about the multiplication principle, but rather shows the whole logic behind the questions with full proofs. The book should be for a first-year-student in college. Do you know a good book on the subject?
Thanks.

If the student's leaning towards computer science at all, I'd recommend Knuth et. al.'s Concrete Mathematics. It's full of solid math and has the aim of building mathematical tools for CS. Other than that, a newer addition that looks promising is Russell Merris's "Combinatorics, 2nd ed." It gives a pretty broad introduction while also giving in-depth work and examples.
