In preparation for the distinguished International Mathematical Olympiad (IMO) competition, each participating country selects the top six high school students every year through a series of national olympiads. These students are invited to participate in the IMO, usually held in July. The IMO is a two-day contest where each day competitors are given three problems which they work on independently. The IMO host country appoints a special committee to which each country submits up to six problems. From this composite "longlist" of problems, a "shortlist" of 25-30 problems is created. The jury, consisting of one professor from each country, makes the final selection from the shortlist a few days before the IMO begins.

The IMO has sparked a burst of creativity among enthusiasts to create new and interesting mathematics problems. It can be safely said that the IMO and shortlisted problems are among the well-crafted problems created in a given year. This book attempts to gather all of these problems with their solutions. In addition, the book contains all the available longlist problems, for a total of more than 2000 problems.

 
From the reviews of the first edition:

"The International Mathematical Olympiad, or IMO is the premier international competition fortalented high school mathematics students. . This book collects statements and solutions of all of the problems ever set in the IMO, together with many problems proposed for the contest. . serves as a vast repository of problems at the Olympiad level, useful both to students . and to faculty looking for hard elementary problems. No library will want to be without a copy, nor will anyone involved in mathematics competitions ."

- (Fernando Q. Gouvêa, MathDL, March, 2006)