A collection of stamps, First Day Covers, cachets, and commemorative stamps relating to baseball. These were issued in the United States and countries around the world. They were issued for a variety of reasons including baseball centennials, anniversaries of special events, opening day of particular teams or stadiums, All-Star and World Series games, and specific baseball players. There are individual stamps, as well as sheets. Other subjects include the Negro Leagues, Women's Leagues, Olympics, American Legion, Little League, and professional leagues from other countries.