Subseries contains unpublished and published letters-to-the editor, including submissions and responses to articles in The Beaver, Bravo, University of Toronto Bulletin, The Globe and Mail, Musicanada (Myra Grimley), Musicworks, National Geographic, Saturday Night, SoundNotes, TSO News, The Torch (University of Victoria), Toronto Star, The Varsity, and Words and Music.
Subseries also contains incoming and outgoing correspondence that John Beckwith designated as "diatribes" or "critical correspondence" with Murray Adaskin, Michael Albano (University of Toronto), Wray Armstrong (Toronto Symphony Orchestra), Bank of Nova Scotia, Elaine Calder (Canadian Opera Company), June Callwood, Care Canada, Adrienne Clarkson (CBC), COC Marketing, COC Publicity, Robertson Cochran (Globe and Mail), James Craig (University of Toronto), Gloria Dent (Guelph Spring Festival), Bronwyn Drainie, Howard Dyck (CBC), Edmonton Opera Guild, Esprit Orchestra, Michael Finlayson (University of Toronto), Fodor's Travel Publications, Jessica Fraser (Toronto Theatre Alliance), Jim Garrard (Toronto Arts Council Foundation), Wayne Gooding (Opera Canada), Michael Goodwin, Joanne Gradzinski (Guelph Spring Festival), Barbara Hall (Toronto City Hall), Dan Heap MP, Linda Hutcheon, William Kilbourn, Alison Latham (Oxford University Press), Murdo Mackinnon, Rick MacMillan (SOCAN), Lynn McDonald MP, Joanne Morrow (Canada Council), Ontario Court, Orchestras Canada, Robert Pritchard (University of Toronto), Doreen Rao (University of Toronto), John Reid (Canadian Music Centre, Calgary), Jeffrey Richards (Lancaster University), Robert Rosevear, St. James Press, Rodney Sharman, Georg and Tanya Tintner, William Toye, (Oxford University Press Canada), University of Toronto Parking Office, Blanche Lemco van Ginkel, Hazel Walker (Toronto Musicians' Association), and Tara Wilson (University of Toronto President's Circle).