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.

Frobisher's papers comprise a letterbook of the North-West Co. containing copies of letters written by Frobisher from April 1787 to October 1788, two original letters to Simon McTavish, 1796, and one from him, 1787, business and legal documents, largely concerning the estate of James McGill, 1810-1834, and a diary, 1806-1810, mostly a record of where he dined.

There is business correspondence, 1792-1800, with letters from among others Alexander Mackenzie, Joseph Frobisher, Alexander Henry, Simon Fraser and Roderick Mackenzie. There are also minutes and resolutions of the Executors of McTavish in a bound volume; and a contemporary copy of the minutes of the executors of his will, 1805.

This collection consists of contemporary copies of letters written by T. Blackwood from Michilimackinac to James and Andrew McGill & Co., to Ch. Chaboillez, and to T. and J. McGregor.

The collection contains correspondence, curriculum vitae, a poem written by his wife, Elizabeth Turnor, a record of medical examinations for the Coroner's Court of Montreal, 1894 and lectures notes. The greater part of the notes consists of embryology notes made at the Anatomisches Institut, Munich, around 1900.