The John Charles Thomas papers, 1903-1991, contain personal papers, scores, correspondence, ephemera, and recordings. Series 1 includes manuscript and published scores. Series 2 contains various concert programs featuring performances by Thomas. Series 3 contains publications and clippings including magazines, newspaper clippings, and magazine clippings.

Series 4 contains correspondence, personal papers, and business papers. A large portion of the series includes scripts from films and radio programs. Another large portion of the series includes manuscript copies of an unpublished biography of Thomas written by Merle Armitage, who was once Thomas's manager. Materials created by archives staff in the course of preparing for the Peabody exhibit on Thomas in 1991 have been retained in this series. Included is correspondence, photographs, and inventories of the sheet music collection. Series 5 contains personal realia and other ephemera that belonged to Thomas, including costumes, trophies, and framed artwork.

Series 6 contains photographs from Thomas's performances, appearances, and personal life. Also included are scrapbooks containing clippings and photographs from various performances. Series 7 contains recordings of live performances and radio programs. The recordings are on magnetic wire, reel-to-reel, audiocassette, and 45- or 78-rpm records. A few have been transferred to CD.

This collection contains racist and culturally insensitive materials, including photographs of Thomas in blackface, photographs of a "Romany Chorus" whose white singers pose in stereotypical Romani costumes, and a number of musical scores and recordings that contain lyrics or images that are derogatory to African Americans and other racial or ethnic groups.