The Earl Noldin Papers contain material documenting Noldin's activity within the rail unions, and his work as an organizer for the Industrial Workers of the World (I.W.W.). Types of material include personal and union-related correspondence including letters between Noldin and a prison inmate, Dan Crombie; union card and dues books; a large scrapbook of articles written by Noldin for the I.W.W. newspaper Industrial Worker; an incomplete set of United Railroad Operating Crafts (UROC) newsletters; and photographs. The earliest correspondence is dated 1917; more recent materials include correspondence dated 1967 and newsletters and clippings from the late 1960s to 1971, with the bulk of the material from the years 1943-1967.