 Michael Heilperin claimed that Mantoux demonstrated that Keynes greatly overestimated the damage done to Germany by the Versailles Treaty and that he had considerably underestimated the capacity of Germany to pay.The experience of the interwar years, according to Heilperin, demonstrated that Keynes had got it wrong.William Rappard said that Mantoux's book was a "very careful, thoughtful, and well-informed refutation of the brilliantly successful but eminently unfair, misleading, and supremely pernicious efforts of Keynes to discredit the peace treaties of 1919" and concluded that Mantoux's book was a "product of the most painstaking scientific craftsmanship and of a political sagacity for which many elder men may well envy its youthful author".