In addition to his many books, Shotwell was co-author of several studies on international relations and was the editor of a series of 150 volumes of the Economic and Social History of the World War as well as a series of 25 studies on Canadian-American relations, both sponsored by the Carnegie Endowment for International Peace. He also contributed nearly 250 articles to the 11th edition of the Encyclopædia Britannica. He co-authored The Diplomatic History of the Canadian Boundary, 1749-1763 with Max Savelle.
