The Harry B. Baker papers consist of artwork, correspondence, ephemera, and photographs produced, received, and collected by Harry Baker. A small percentage of the collection pertains to Maud Baker, Harry's wife and a fellow artist. The papers include documentation of a personal and a professional nature.

The General series includes a variety of textual materials and ephemera, such as a marriage certificate, identification cards and licenses, and receipts relating to Baker's death and burial. Correspondence in the series includes postcards and letters from New York School of Fine and Applied Art colleagues Frank Alvah Parsons, Robert Castle, and Betty Carter, as well as from unidentified individuals, possibly former students. Of note is a 1928 letter from Parsons advising that he has abolished the school's student government.

The Artwork series consists of drawings, paintings, and sketches in a variety of media, including charcoal, pencil, ink wash, and watercolors. Much of the artwork depicts frontier settings, often populated by horses and cowboy figures, although some drawings depict busy urban scenes with women, children and laborers. Cartoons and caricatures of clowns, cowboys, hobos, and minstrels are also present. The series includes proofs of a cover of Western Story magazine featuring an illustration by Baker.

The Photographs series consists of negatives and prints documenting Harry Baker's travels and teaching activities. Many photographs depict Baker with his students engaged in classwork and recreational activities, such as men's life drawing classes, a plein-air painting camping trip with male students, and a visit to Riverside Park in New York City. There is a humorous element to many of the photographs, such as a staged scene in which Baker appears handcuffed by a gun-wielding sheriff. Twelve prints and their accompanying negatives depict what may be either a Wild West show or the filming of a motion picture in the Western genre. With the exception of one print labeled 1929, none of the photographic materials are dated.