This work provides biographies of more than 500 men and women who have served as admiral, vice admiral, or rear admiral. While officers from the U.S., British, French and Japanese navies make up the bulk of the work, officers from 22 countries, including Australia, Canada, Germany, India, Italy, the Netherlands, Russia, and Spain, are also included. The main criterion for inclusion is that each person must have actively served in the rank of at least rear admiral, but not necessarily in enemy action. This effectively rules out people who were granted the rank on retirement, as a courtesy title or posthumously. The book also includes lists of admirals organized by nationality and by year of birth.