Paul Samuelson is widely regarded as one of the greatest economists of the twentieth century and possibly of all time. This chapter summarises his vast contributions across a number of areas of economics. After a brief section covering autobiographical details, we consider some of the groundbreaking material contained in Foundations of Economic Analysis, followed by sections on consumer theory and welfare economics, capital theory, dynamics and general equilibrium, international trade, finance and macroeconomics. The penultimate section looks at the crucial role that Samuelson played in turning the economics department at the Massachusetts Institute of Technology into one of the best in the world. The final section provides some concluding comments.