This third edition of Introductory Combinatorics contains extensive rewriting of some sections and the inclusion of some new material and exercises.There is enough material in this third edition for a two semester course. A first semester could have an emphasis on counting and a second semester an emphasis on graph theory.
It is difficult to assess the prerequisites for this book. Perhaps they can be best described as the mathematical maturity achieved by the successful completion of the calculus sequence and an elementary course on linear algebra. Use of calculus is minimal, and the references to linear algebra axe few and should not cause any problem to those not familiar with it.