The subseries contains correspondence to and from Canadian and international musicians, colleagues, music ensembles and organizations. Musicians and colleagues include among others Samuel Dolin, John Weinzweig, John Beckwith, Alan Gillmor, Robert Aitken, Bruce Mather, John Rea, Alcides Lanza, Jonathan Harvey, Sydney Hodkinson, Othello Liesmann, Mario Bertoncini, Barbara Monk Feldman, Vivienne Spiteri, Stanley Sadie, Eckart Schloifer, Osher Green, Mario Bernardi, Victor Feldbrill, Max Lifchitz, Hayes Biggs, Louis Philippe Pelletier, Bengt Hambraeus, Elmer Isler, Rivka Golani, Hope Lee, Janina Fialkowska, David Eagle, Alex Pauk, Erica Goodman, Thomas C. Plaunt, Robert Cram, Paul Vaillancourt, Jean-Yves Gicquel, Katharina Hanstedt, Antonio Lysy, Philip Mead and Henri Bok.
The subseries also contains correspondence from the Canadian Broadcasting Corporation (CBC), the Canada Council for the Arts, the Canadian Music Centre, the Ontario Arts Council, the Canadian Music Council, the Canadian League of Composers, as well as correspondence from performing rights organizations such as BMI (Broadcast Music, Inc.) Canada Limited, PRO Canada (Performing Rights Organization of Canada Limited), CANAMEC (Mechanical Rights Division of Performing Rights Organization of Canada Limited), SOCAN (Society of Composers, Authors and Music Publishers of Canada), the SOCAN Foundation, and SODRAC (Society for Reproduction Rights of Authors, Composers and Publishers in Canada).
The subseries also includes correspondence from the Toronto Symphony Orchestra, Orchestre symphonique de Montreal, Orchestre symphonique de Québec, Nouvel ensemble moderne (NEM), Sociéte de musique contemporaine du Québec (SMCQ), the National Arts Centre, Piano Six, New Music Concerts (Toronto), Contemporary Music Showcase Association, the Stratford Festival, Vega Wind Quintet, the Chilingirian Quartet, Contra-Trio, Organizacion de Los Estados Americanos, World Saxophone Congress, Rijksuniversiteit Utrecht, Instituut voor sonologie, the American Musicological Society, Composers' Forum Inc., the S.C. Eckhardt-Gramatté Competition, North South Consonance Inc., Washington Square Contemporary Music Series, the International Music Council, the Banff Centre, School of Fine Arts, the National Youth Orchestra of Canada, International Society for Contemporary Music (ISCM), the Eastman School of Music, Trio Basso, the Esprit Orchestra, Vancouver New Music, Concours international de musique de Montréal, Le Domaine Forget de Charlevoix inc., Société québécoise de recherche en musique, Ensemble contemporain de Montréal, Conseil des arts et des lettres Québec, Huddersfield Contemporary Music Festival and Radio France, among others.
In addition the subseries contains correspondence from music publishers including Jaymar Music Ltd. (Iroquois Press), Waterloo Music, Les editions Doberman-Yppan, G. Ricordi & Co. (Canada) Ltd., Boosey and Hawkes (Canada) Ltd, the New Grove Dictionary of Opera (Macmillan Press Ltd.), and International Who's Who in Music (International Biographical Centre, Melrose Press Ltd.)
