The initial collection consists of several hundred unpublished poems written by Margaret Avison between 1935 and the late 1970s. The second accession, received in 1996, consists of correspondence from various literary associates between the 1950s and the mid-1990s. In several instances other writers and poets send samples of their work for Avison's comments. There is a lengthy correspondence between Avison and the American poet Fredrick Bock. The Collection includes two theses about the works of Margaret Avison and several of her unpublished essays and poems.

The third accrual consists of photographs, audiotapes, and material relating to Avison's work such as worksheets, manuscripts, published copies, and reviews. It also includes correspondence from the 1980s to 2001.