Most of James' research papers stem from his Philadelphia period. The bulk of this material is research files. Approximately 7.5 m of general research files contain notes, extracts, printed materials, correspondence and some teaching materials, largely on economic history with special emphasis on banks, but also including some papers from the 1940s on education and war-time problems. A second category (approximately 1 m) is devoted to the history of banking. Again, these consist largely of notes and extracts, including extensive typed extracts from the business papers of Chicago banker James B. Forgan (active 1900-1917), but there is a component portion of original materials, for example, office correspondence of Pinkerton's Detective Agency (1870s-1880s) and essays and addresses by consulting economist William Wallace Goforth (approximately 1930s). A third category comprises about 15 cm of notes on research methods. Finally, James created three large card-files: one a bibliography-index on economic topics, history and institutions, the second a chronology of 18th and 19th century economic history, and finally a series of larger, more discursive note cards on economic history. There are manuscripts and typescripts of the various drafts and revisions of many of James' publications, particularly The Economics of Money, Credit and Banking, Growth of Chicago Banks, England Today and The Road to Revival. There are also copies of his M.A. and Ph.D. theses, as well as drafts of about half a dozen articles, largely on shipping, from ca 1925 to ca 1933.

Most of the materials pertaining to James' work as an economic consultant are from the post-war period. These include 12 cm of speeches, correspondence and reports on post-war economic issues, 5 cm of draft reports and briefs for the Tremblay Commission (1953), 30 cm of correspondence, notes and reports pertaining to the Conseil d'Orientation Economique du Québec (1961-1962), and documentation illustrating James' involvement in the appraisal and re-organization of the Wharton School (1956-1957).