The fonds consists of correspondence and subject files pertaining to various locals of the International Association of Machinists. Also included is material from the B.C. Federation of Labour, Canadian Congress of Labour (1970-1984), Ontario Federation of Labour (1972- 1977), the provincial and federal CCF and NDP, as well as other material pertaining to labour and politics. There are also tapes of radio broadcasts and material relating to Thayer's personal interests.

The fonds consists of minute books of both regular meetings (1889-1956) and other Council Executive Board (1907-1920) of the Vancouver Trades and Labour Council (VTLC), affiliated union files and subject files of the Vancouver and District Labour Council (1956-1983). Fonds also includes minutes from the B.C. Federationist (1912-1922), the Vancouver Labour Temple Company (1909-1920), the Oil Refinery Workers' Union (1918-1921) and an address book with clippings from the British Columbia Federation of Labour (CLC).