This paper explores Samuelson's concept of the neoclassical synthesis. It is argued that his two main books hold out different types of synthesis. Foundations offered a synthesis based on common mathematical structures and presages the attempts to synthesize economics by Don Patinkin and Robert Lucas. In contrast, the neoclassical synthesis of his introductory textbook, proposes a more limited synthesis, based solely on policy. It linked the theory of income determination not with mathematical microeconomics based on optimization but with microeconomics rooted in interwar institutionalism, involving oligopoly and non-maximising behaviour.