This paper investigates Irving Fisher's debt-deflation theory of the Great Depression by examining two important questions. First, might the deflation of the early 1930s have been "anticipated"? Data on prices and interest rates are used to show that the answer is yes. Second, why was there no depression following the 16% deflation of 1920-22? If debt grew substantially between the two deflations, the difference would be understandable. But again, there is evidence that private debt did not increase sufficiently from 1922 to 1929 to explain why one deflation was followed by a boom while the other was followed by a bust. The paper goes on to provide a new interpretation of the deflation of the 1930s that concentrates on the consequences of anticipated deflation. Sustained, anticipated deflation is studied in the framework of a general equilibrium monetary growth model. The model shows how temporary declines in money growth lead to a collapse in both consumption and investment.