A.C. Pigou’s The Theory of Unemployment and its Corrigenda: The Letters of Maurice Allen, Arthur L. Bowley, Richard Kahn and Dennis Robertson

Shortly after the appearance of the first printing run of A.C. Pigou’s The Theory of Unemployment, Macmillan and Company made available to purchasers a Corrigenda slip. Reviewers of the book identified additional errors and slips, particularly in Pigou’s mathematical work. This paper considers the broad evolution of Pigou’s economic thought on unemployment and the implications of unpublished correspondence discovered in the Marshall Library archives alerting Pigou to errors appearing in the first printings of The Theory of Unemployment. Pigou’s departure from the Marshallian tradition of placing mathematics in the background of economic theorising, and reasons why his 1933 text required a substantial corrigenda, are examined. It is argued that the impact of Pigou’s treatise on unemployment on the development of economic thought extended beyond its contributions to unemployment theory.