The Hellmuth Wolff Organ Collection consists primarily of organ plans, pamphlets, photographs, books and periodicals, and personal correspondence. The majority of these documents are associated with or represent one of the fifty organs in Wolff’s opus. In addition to depicting Wolff’s instruments, the collection of organ plans also includes Wolff’s drawings for proposed but not-constructed organs, plans by other organ builders, and plans drawn by Wolff that are based on historical models and treatises by writers such as Dom Bédos. Of the photographs, most are associated with specific Wolff organ projects and represent a span date of the late 1960s to the early 2000s. Also in the photograph collection are images of historical organs in Europe, which Wolff presumably used in modelling and designing several of his instruments, as well as images associated with other organ projects by builders such as Casavant Frères, Karl Wilhelm, and Rieger, all of whom Wolff worked with before establishing his own workshop in Laval. The collection of pamphlets includes programs, program notes, and concert series information for several of the Recitals and concerts performed on Wolff’s instruments. Of the periodicals and books, titles include The American Organist, Choir & Organ, and Orgelforum. Also in the collection are several three-dimensional models, or maquettes, of Wolff organs.