Appropriate for one- or two-semester, junior- to senior-level combinatorics courses. This trusted best-seller covers the key combinatorial ideas--including the pigeon-hole principle, counting techniques, permutations and combinations, Polya counting, binomial coefficients, inclusion-exclusion principle, generating functions and recurrence relations, combinatortial structures (matchings, designs, graphs), and flows in networks. The Fifth Edition incorporates feedback from users to the exposition throughout and adds a wealth of new exercises.