This printers, publishers and booksellers index is modeled after Bristol's Index of Printers, Publishers and Booksellers Indicated by Charles Evans in his American Bibliography. Each entry contains a name and place, with item numbers listed underneath by date. Personal names are listed in the most complete form that could be determined. Corporate names are listed in the form used by the Library of Congress. Newspapers and magazines are entered by their full titles as recorded in Brigham's American Newspapers, 1821-1936 and Union List of Serials. Also included is a geographical index by city and a list of omissions with explanations.

Beginning in 1924, Proceedings are incorporated into the Apr. no.