University of Michigan group established in 1946 devoted to production of Gilbert and Sullivan operettas. Records include production files with programs, photographs, reviews and newspaper clippings, and scattered production notes and memoranda; topical files relating to the Society, its friends organization, and its publication; slides of productions; Society newsletter, "Gasbag"; posters; phonorecords, tapes, and videos of productions.
The records of UMGASS have been divided into ten series: Slides, Topical Files, Production Files, Posters, Memorabilia Volumes, Magnetic Tape Recordings, Sound Recordings, Audiotapes, Videotapes, and Scrapbooks. Because materials on one production can include photographs, scrapbooks, recordings, or slides- all of which live within different boxes of the collection -- a directory has been compiled in the Production Files series. The directory lists the year and title of the UMGASS production for which the library has materials and a lettered key exists that denotes the physical existence and location of materials within the collection.