The Editor-in-Chief's records comprise the largest series in the six series described in this inventory. James Marsh was hired for this position, and he assumed responsibility for the encyclopedia editorial staff, as well as for editorial policies, stylistic uniformity, cartography, illustrations, indexing and related editorial concerns. The series is primarily textual in format, and provides an in-depth view of the editorial policy practiced by the staff of the Canadian Encyclopedia. The Editor-in-Chief was the overseer of daily operations, and the communicating link between the President and Vice-President of the Company and the editorial staff. Mr. Marsh was often the individual assigned to deal with media and public relation events, and corresponded with the public, as well as the consultants and expert readers. The records are in good physical shape.

The Editor-in-Chief's files have been arranged into the following four sub-series: Editor-in-Chief's files; Editing files; Cartography files; and Illustrations and Photographs administrative files. Mr. Marsh assumed responsibility for final editing decisions, as well as for the administration of cartographic and illustrative inserts for the Canadian Encyclopedia. The largest of these sub-series is 3.1: Editor-in-Chief's files. Included here are general correspondence and memoranda files, editorial staff meetings and reports, Marsh's free-lance editorial and personal publishing files, and his assistant's (Micaela Gates) files. The editing files also contain information related to design and printing, promotion, style and format, and reference material for editors.
The series title is based on the contents of the records.