Michael Heilperin was a friend and colleague of Ludwig von Mises's in Geneva, and his specialization was the international monetary system. He applied the Austrian theory of the business cycle along with his knowledge of the balance of payments to warn against the rise of monetary nationalism. He wrote against the monetarist idea of floating fiat currencies and in favor of an international gold standard, and said that the debate was really between monetary chaos and international monetary stability. This 1939 work remains a definitive study of the author's times and our own.