This collection consists of letters written by Canadian soldiers serving in the Second World War, between 1943 and 1944. The letters were written to family members or romantic partners, while the soldiers were in training in England, or deployed in Europe. The collection also includes some letters written to the soldiers. Contents of the letters chiefly concern news from home and the daily life of soldiers.

The collection is divided into three series, one for each soldier. Series 1 contains correspondence between Robert C. Parsons and his wife, Peggy Parsons. Series 2 contains correspondence between Jack Mills and his mother, C.I. Mills, and brother, Bob Mills. Series 3 contains correspondence between A.V. "Mac" Cormack and his girlfriend Florence Morgan Graham, as well as a letter from Mac's roommate G.D. "Jerry" Royds, also to Florence.

Collection consists of 59 heraldic plaques featuring Royal Navy and Royal Canadian Navy badges for ships and naval installations.

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.

The collection consists of a selection of records reflecting Sir Arthur Currie's tenure as Principal of McGill University from 1920 to 1933. His administration was marked by the establishment of the Faculty of Music, the School for Graduate Nurses, and the Faculty of Graduate Studies and Research. Constructed during this period were Moyse Hall, the Roddick Gates, a Biology Building (now the F. Cyril James Administration Building), and additions to Royal Victoria College and Redpath Library. Currie died in office on 30 November 1933. His records form a part of the McGill University's executive and administrative records, RG2: Office of the Principal and Vice-Chancellor. The Principal is the academic head and chief administrative officer of the University. Under the original Charter of 1821, the Principal constituted with the Board of Governors and the Fellows (now the Senate) a body politic and corporate. Later amendments to the Charter and changes in the University statutes have not significantly altered the position of Principal. Ex officio, by virtue of his office, the Principal is also Vice-Chancellor of the University, a member of the Board of Governors and Chairman of the Senate. Frequently, it has been the Principal's vision and personality which have determined the course of McGill's development; therefore, the records not only document the administrative activities of the office, but also often reflect the character of the whole institution. Currie's records fall more or less into the three general series: external correspondence, internal administration and academic matters.

The Sir William Osler Collection, distinct from the Bibliotheca, is an extensive archival holding of Osler's correspondence (including eighteen hundred original letters), daybooks, accounts, engagement books, legal documents, book invoices, membership certificates, notebooks, lectures, addresses, newspaper clippings, photographs, books with manuscript additions, and miscellaneous loose items formerly inserted into individual books in his library. The collection also contains various family papers, including correspondence of Lady Grace Revere Osler and Edward Revere Osler.

Collection consists of programs related to an appearance by Harry Belafonte in Montreal in support of the Society to Overcome Pollution's environmental aims. Also contains a clipping, manuscript notes, and a typescript signed Mona Elaine Adilman about Quebec environmental legislation.

The Sonde Collection provides a thirty-five year span of documentation for a Montreal-based Canadian experimental musical group who were very active electroacoustic composers and performers in the 70s and 80s. Sonde (formerly named MUD, Musical Design), created and played sound sources in Quebec, Canada and Europe. Sonde’s compositions were generally conceived for live performance on original sound sculptures. Using meditative improvisation, the group produced new music with sounds created by electroacoustic amplification and transformation.
The Sonde Collection is divided into 26 series and contains approximately 1,900 items. The majority of the collection consists of correspondence, concert posters and programs, and audio and video recordings. Activities of the Sonde group are described together as Sonde Papers and the activities of Charles de Mestral, a founding member of the group as Charles de Mestral Papers.
In the Sonde Papers, whenever it has been possible to do so, each item is referenced to the events listing, a numbered, chronological listing of events created by the group, entitled: ACTIVITES DU GROUPE SONDE (1975-2010) / Sonde Activities (1975-2010). The Sonde Papers include posters, programmes, scores, photographs, audio and video recordings.
The Charles de Mestral Papers are the personal items of Charles de Mestral, a member of the Sonde group from its inception. Whenever it has been possible to do so, each item is referenced to the events listing entitled: RÉALISATIONS DANS LE DOMAINE DE L’INSTALLATION SONORE (1985-2013, Charles de Mestral) / Sound Installations (1985-2013, Charles de Mestral) a numbered, chronological list of activities of Charles de Mestral. The Charles de Mestral Papers include scores, correspondence, installation plans, clippings, audio recordings and publications.

Collections consists of theater, music, and dramatic productions, between 1911 and 1915, collected by T. Wesley Mills.

The collection consists of 287 negatives, 65 prints and 179 copy negatives from photographer Tappan Adney. The collection documents his passage in the Yukon, Alaska and British Columbia during the Klondike Gold Rush in the late 1890s. The negatives depict various geographic landscapes, people and animals, settlements, and day-to-day mining activities in numerous locations, such as, Dawson, Skagway, Lower Yukon, Bonanza Creek, El Dorado, Chilkoot Trail, Nome, Dyea, Skookumchuck, Hunker Creek, Tagish and Dutch Harbor.

The Taylor White Collection is comprised of 938 watercolour paintings of mammals, birds, fish, and reptiles. White, a British jurist, commissioned various artists of the day (including Charles Collins, Peter Paillou, Jacob Van Huysum, George Edwards, and Eleazar Albin) to paint these animal portraits from live and dead specimens brought back to England from around the world. Many of the paintings are accompanied by loose-leaf manuscript notes, written mainly by White in Latin, providing further information about the animal; transcriptions and English translations of these notes have been provided within the record for each painting.