Samuelson’s Foundations of Economic Analysis did much to define the way economic theorizing was undertaken after the Second World War. It was important both because of its contents—it provided an up-to-date toolbox for doing economics— and because Samuelson, despite being only thirty-two when the book was published, was already a well-known figure.
He was widely considered the star of the generation of economists that had come of age during the Second World War, acknowledged by the award of the AEA’s first Clark Medal. He was already making his mark at MIT, where his presence was a major factor in the transformation of a service department focused on teaching engineers into one of the leading American economics departments. His articles on fields as diverse as consumer theory, international trade, business cycle theory, and the Keynesian multiplier demonstrated the way mathematics could be used to resolve confusions in literary accounts of economic theory. This gave Foundations, the long-awaited revision of his PhD dissertation, a significance it would not otherwise have had.
As economics became progressively more mathematical, with graduate students increasingly expected to construct formal models of maximizing consumers and firms, Foundations was widely seen as the canonical exposition of such methods. In addition, it was an important resource for anyone tackling dynamics or welfare economics.
from Roger E. Backhouse, ‘Revisiting Samuelson’s Foundations of Economic Analysis’, Journal of Economic Literature, 2015, pp. 345-346.
The Ideas of Economists 