The collection includes extensive holdings of jazz, blues, country and popular music; historic voices and authors reading their own works; vintage radio programs; classical and opera. The Marr holds a wide range of historic formats including LPs, 78s, 45s, cylinders, transcription discs, instantaneous-cut discs and open-reel tapes. The archives maintain sound recordings for a number of archival for collections shared with LaBudde Special Collections. The recordings in Marr, currently numbering over 325,000, do not circulate but listening stations are available in the Archives.
