A collection of correspondence, telegrams, notes, postcards starting in 1860 to present. These are between team owners, owners and players, or between friends. The letters are either handwritten or typed. The oldest letter is dated 1860 between brothers, describing a 'new' game of baseball. There are personal career recollections, game challenges, as well as baseball-related topics from Minor Leagues, AAGPBL, and collegiate games.

A collection of correspondence between Cy Jones and notable baseball athletes and executives, and one umpire, dated between 1939 and 1961.

The collection contains audio interviews conducted by Dale Shellman with a variety of baseball players, managers and others associated with the game. The recordings are on micro audiocassettes. The interviews were most likely conducted in the mid-1980s.

A collection of newspaper clippings, correspondence, statistics, research notes, and photographs related to the Ferrell family, dated 1911-2005. This was created and/or compiled by Dick Thompson for his book on the Ferrell brothers.

A collection of correspondence, articles, research notes, and clippings created and compiled by Dick Thompson, primarily related to baseball in New England.

The collection documents the photographs taken by Don Wingfield between 1950 and 1970. Of particular interest is the large number of photographs capturing players from the Washington, D.C. area, including the Baltimore Orioles and Washington Senators (1901-1960). Subjects of particular interest include Baseball Hall of Famers, Rookies of the Year, and minor league players.

A collection of ephemera relating to a wide variety of baseball-related subjects on professional and amateur leagues, on teams, players, post-season games, patents, tours, stadiums, etc.

This collection contains correspondence between F.C. Lane and numerous baseball players and officials between 1911 and 1936. Lane was the editor for Baseball Magazine during that time, and most of the correspondence with players referred to their off-season activities, some of which he included in issues of the magazine. Other themes that received attention included betting in ball parks, the World Series, the Federal League, and World War I.

A collection of 69 scrapbooks relating to the career and personal life of Frankie Frisch. Although the majority of the collection consists of newspaper and magazine clippings, the scrapbooks also contain correspondence, original photos, programs, radio scripts, and certificates. These are dated between 1913 and 1969.

The collection documents George Weiss' tenure with the New York Yankees minor and major league organizations from 1932 to 1960 and the New York Mets major league organization from 1961 to 1966. It includes financial records, player reports, ticket files, correspondence, clippings, personnel files, scouting evaluations, ephemera, tour files, marketing and promotion files, and personal documents.