In the interwar years (1919-39), macroeconomics was at the forefront of attention of both thinkers as well as policymakers. This paper focuses on Hawtrey, one of the major economists of that period, whose contemporary influence on macroeconomic theory as well as policy was significant, but whose contributions, in the aftermath of World War II, have gone largely into oblivion. We begin with a brief exposition of the main strands of Hawtreyan macroeconomics. We then try to demonstrate the significant influence that Hawtrey's ideas had on Keynes's views, highlighting both the areas in which their ideas differed and where their views reinforced each other's. Before concluding, we draw attention to at least five contributions of Hawtrey, which have a strong claim to be considered original but have received scant professional credit: the multiplier, the accelerator, quantitative easing, crowding out and the announcement effect of monetary policy.