Fonds consists of papers pertaining to Adair's student days and scholarly publications prior to coming to McGill, and his teaching activities at McGill. There are no materials relating to his administration of the History Department or his presidency of the C.H.A. Records of Adair's student days include diplomas, examination papers, lecture syllabi and reading lists from the universities of London and Cambridge, and printed testimonials on his behalf, 1911-1918.

Drafts for scholarly publications on English constitutional history for the years 1916-1928 can be found in manuscript and proof form, as well as correspondence relating to his publications and the reviews they received, 1947-1955. Adair's research materials comprise notes and draft articles on the history of Québec parishes. Records of his teaching career at McGill include notes for lectures, a register of student marks (Restricted), formal examination papers, course outlines and copies of class notes from 1925 to 1954. Adair's family life is documented by a collection of photographs and glass negatives, largely of Adair himself as a child and young man, with family and school friends.