The Charles Reiner Collection consists of correspondence, newspaper reviews and clippings, performance programmes, personal documents including legal material, photographs, writings, published and unpublished music by Reiner and other composers, audio and visual recordings of Reiner and other performers, books, and awards. Of particular interest is correspondence from Rudolf Serkin, Alfred Cortot, and Kurt Waldheim; legal documents from both before and after Reiner’s immigration to Canada; and the extensive collection of programmes and newspaper clippings that document Reiner’s extensive performance career.

The Julius Schloss Collection consists of Julius Schloss’s complete portfolio of published and unpublished compositions, sketches, studies and analyses. In addition, it contains documentary artefacts, including correspondence, newspaper, magazine and journal clippings, concert and competition programs, media reviews, and photographs, that chronicle both the early life of this German-Jewish composer in Europe and his later days in exile in Shanghai and the United States.
The content of the collection pertains to several lines of historical research: First, Schloss’s close relationship with Alban Berg as a personal assistant and chief copy editor, as well as his interaction with other contemporaries in Vienna during the 1920s, may offer new insight in studies of the Second Viennese School. The items of Bergiana, including a handwritten Baudelaire poem by Berg which served as a “secret program” to the Lyric Suite and a selection of correspondence surrounding Berg’s last wishes for the Lyric Suite score, are particularly valuable. Second, Schloss’s ten-year exile in Shanghai, documented in assorted correspondence, programs, reviews and miscellaneous artefacts, may provide a new account of the Shanghai generation. Finally, the continuation of Schloss’s life in the United States as a struggling composer and teacher bears witness to the difficult conditions for the American émigré population after World War II.

Paul Helmer’s "Growing with Canada" Collection constitutes an important resource for research in Canadian music and culture of the twentieth century. Canadian music and culture of the twentieth century. The Collection has been divided into seven series and contains approximately 1 140 items. Of particular interest are the edited interview transcripts (S.1 and S.7, available in print and .pdf, respectively), which Dr. Helmer had intended Paul Helmer Finding Aid Page 3 of 18 17 July 2014 as the second volume of his project. The Collection also contains the raw material for these edited transcripts: namely, the unedited transcripts and audio recordings themselves, as well as biographical information for each “émigré” musician discussed (with correspondence, copies of source material and photographs), copies of primary and secondary sources on immigration and internment, and miscellaneous items, including correspondence, unused research materials and notes relating to the book launch for "Growing with Canada".

The Roger Doucet Collection consists of over 1000 pieces of sheet music (including scores), 45 manuscripts, and one scrapbook containing photographs and newspaper clippings related to his career as the singer of “O Canada” during professional sports games.

The Montreal Mendelssohn Choir Collection comprises several volumes of sheet music from the Choir’s library. The choral folios were compiled and bound into eight volumes at the time of their donation to McGill University in 1895. The estate of D. Torrance Fraser, a former Choir member, donated another four volumes of choral music in 1926 and 1927. Three volumes contain second copies of the pieces from the Choir’s library donated thirty years prior; the fourth volume donated in 1927 contains a number of pieces performed by the Choir but not found in the seven extant volumes from the Choir’s library.