Every year there is at least one combinatorics problem in each of the major international mathematical olympiads. These problems can only be solvedwith a very high level of wit and creativity. This book explains all the problem-solving techniques necessary to tacklethese problems, with clear examples from recent contests. It also includesa large problem section for each topic, including hints and full solutions so that the reader can practice the material covered in the book. The material will be useful not only to participants in the olympiads and their coaches but also in university courses...