This chapter examines the relationship between economists at MIT and the University of Cambridge. The “two-Cambridges” controversy over the theory of capital, the production function and the determination of the rate of profit is discussed from the MIT perspective. It is argued that the close personal connections between the two groups of economists, notably between Paul Samuelson, Robert Solow, Joan Robinson and Frank Hahn, were crucial. A little-noted outcome of the debates was a pioneering paper by Solow and Joseph Stiglitz, an early contribution to work on disequilibrium macroeconomics that became influential in the 1970s as interest in capital theory waned. With Hahn’s appointment as Professor at Cambridge, the dynamics of the relationship between economists in the two institutions continued to be close but changed significantly.