The subjects inquired into by Canadian federal royal commissions have ranged over such a wide field that the reports and special studies prepared by the 400 commissions since Confederation have become an essential part of any research in Canadian studies. In many cases the special studies which are always prepared by the best experts available stand as the most important works ever to appear on a given subject. For example, the studies used by the Royal Commission on Dominion-Provincial Relations (1937-1940) are still used as required reading in both graduate and undergraduate university courses almost thirty years later. In the author's work as Government Documents Librarian, he witnesses the daily use of royal commission material. The importance attached to royal commission documents and the considerable difficulty in locating many of the earlier reports let Henderson to undertake the compilation of this checklist four years ago.