The fonds consists mainly of a bound notebook that Mussen kept with notes on his experimental investigations. Includes mounted photographs of brain specimens and animal subjects. Fonds also contains loose manuscript notes and two overhead projector transparencies.

The fonds includes American Neurological Association material (1934-1941), army files (1939-1943), correspondence, lecture notes, glass slides, large glass negatives, colour screen filters, and reprints with a card index.

1 typed manuscript with hand-written amendments title only.; 1 typed manuscript with hand-written amendments.; 1 hand-written manuscript.; Worksheets.; 2 typed and hand-written manuscripts.; 1 reprint, added to file Nov. 1978.; 2 pieces of correspondence.

1 typed manuscript with hand-written amendments.; Illustration of 1st Foundation volume.; Holograph of title page.; Typed legend.; 1 printed proof with hand-written amendments.; 6 unmounted photographs.; 13 printed photographs (extra).; 1 booklet of page proofs.; 1 set of 14 page proofs.; 1 typed list of staff marked "Urgent".; 2 groups of worksheets.; 1 autographed reprint, added to file Nov. 1978.

1 typed final manuscript.; 3 earlier typed manuscript drafts with hand-written amendments.; 1 reprint added to file Nov. 1978.

The Penfield fonds consists of over eighty metres of Penfield's personal and professional records dating from his childhood up until his death in 1976, including during his career at the Montreal Neurological Institute. The materials in the fonds include photographs, correspondence, manuscripts and drafts of publications and speeches, research notes, glass slides, bound reports, films, and academic gowns.