The collection consists of working files, including letters, brochures, press releases, photographs, and clippings.

The collection contains letters regarding Flaaten's work, recommendations, and appreciation; news clippings about events concerning bands and band members, Flaaten's activities as musical director,  and personal and family events; photographs depicting his work, family, and friends. The collection includes clippings and programs of the Beethoven Chamber Music Club circa 1900–1902.

The collection contains a complete series of administrative records including board minutes, annual reports, committee reports, financial statements, membership lists. The collection also includes publicity files, programs, photographs, scrapbooks and news clippings.