Sous-fonds contains typed copies of approximately 100 letters from Malcolm Lowry to various friends, editors, publishers, and translators of his works. Harold Matson, Albert Erskine, and David Markson are frequently recurring addressees. The only incoming letter to Lowry (also a typed copy) is from Arthur Lowry, Malcolm Lowry’s father.

The sous-fonds also includes a typescript of a prose text of uncertain authorship which in part details Lowry’s 1949 stay at a Vancouver hospital with a broken back and ribs. Excerpts of letters are also included in the prose account.