We stress the following: (1) Pigou reconceptualized economics as a science of economic welfare, arguing that economists abandon the illusion of a general theory of market failure and instead pursue case-by-case investigations, each limited by the complexity and variability of history. (2) Pigou considered the value of analytical techniques as historically contingent. In its high level of abstraction and use of mathematics, The Theory of Unemployment, the target of Keynes’s attacks in The General Theory, was a significant departure from the Marshallian dictum that economic analysis should be accessible to the educated public. (3) Pigou was most fundamentally at odds with Keynes on the latter’s confidence that the market economy was condemned to secular stagnation. In Pigou’s assessment, the signal achievement of The General Theory was the unprecedented explanatory power of its macroeconomic model.