The history of developmental psychology in Canada prior to 1960 is concisely recounted. Discussion begins with an account of the scholarly interests and activities of James Mark Baldwin, who brought modern psychology to Canada, and Frederic Tracy, who objected to child-centered approaches to child rearing. The remainder of the paper focuses on the professional activities and ideas of William Emet Baltz, Canada's first really modern child psychologist, and the work of Mary L. Northway, Donald O. Hebb and Wallace E. Lambert. Baltz's views on learning, emotions, and the child are reported, along with his theory of personality development and, very briefly, his and Mary Ainsworth's research on "security." Subsequently, brief accounts are offered of Northway's development of sociometric techniques and research on friendship patterns, the uses of Hebb's findings in the U.S. and Canada, Lambert's studies of bilingualism and applied research on bilingual education, and developmental psychology in French Canada. In conclusion, it is noted that the pioneers of Canadian developmental psychology came to a common conclusion, namely, that the quality of mental health of individuals in society depends on the quality of the experiences they have had in infancy and early childhood, especially infancy. (RH)