The Commercial Empire of the St. Lawrence, 1760-1850, by D. G. Creighton, was published in Toronto, New Haven and London, 1937 (reprinted 1956 as The Empire of the St. Lawrence). Reflecting the new emphasis on socioeconomic factors that dominated Canadian historical writing in the 1930s, this masterly and elegantly written work deals with the St Lawrence Valley's influence as a transportation system and a focus of economic activity up to 1850. Creighton argued that the geographic nature of the St Lawrence-Great Lakes system made it a rival of systems such as the Hudson-Mohawk route (NY). The natural advantages of the St Lawrence were, however, offset by political decisions, such as those made in 1783 regarding the international boundary, and by the animosity felt by agriculturally based Québec society toward the entrepreneurial class of Montréal.