Collection consists of research material gathered by Johnston for his book "The Voyage of the Komagata Maru: The Sikh Challenge to Canada's Colour Bar" (1979; 1989) and subsequent articles and books about Sikhs in Canada, including (with Tara Singh Bains) "The Four Quarters of the Night: The Life-Journey of an Emigrant Sikh" (1995) and "Jewels of the Qila: The Remarkable Story of an Indo-Canadian Family" (2011). Records in the collection are primarily of photocopied and microfilmed material from archival material held by institutions, newspapers and journals, and notes and drafts.
Collection is divided into the following eleven series: Articles (1988–2016); "The voyage of the Komagata Maru" draft manuscripts (1977–1978); Finding aids, bibliography and essays on sources (1975–1991); Archival documents and research notes ([197-–before 2011]); Official sources files ([1975–after 1996]); Biographical and autobiographical sources files ([197-–198-?]); Individual files (1988–1993); Research studies files ([ca. 1980]–1988); Scholarly articles ([197-]–2000); Periodicals and pamphlets ([198-?]–2014); and Newspaper clippings ([197-]–2014).