He is credited with writing the first introductory textbook that brought Keynesian thinking into American university classrooms,[1] the 1947 Elements of Economics.
He then joined the faculty of Scarborough College, part of the University of Toronto system, and remained there until 1978 as a professor of economics.
In his later years at Glendon College, he taught Intermediate Macroeconomics from his 1984 book, World Economy in Crisis: Unemployment, Inflation and International Debt.
In The Vital Center (1949), author Arthur M. Schlesinger, Jr. describes the attack on Tarshis: The most recent textbook witch-hunt provides an edifying example.
An enclosed review denounced the book for its exposition of the doctrines of Lord Keynes and identified Keynseianism as a form of Marxism.