"In the eighteen months that have passed since this book was published, it has become something of a classic. Almost every recent paper on the Phillips curve or inflation refers to the book, most often in a way that suggests that it succeeds in doing what its title promises, providing a rigorous theory of inflation and unemployment.... The papers by Holt, Phelps, and Mortensen address the second of my three questions: Why is the rate of change of wages inversely related to the amount of employment? ... It strikes me that the elaboration and formalization of this story is the principal contribution of the volume. It does succeed in making sense out of the confused notion of disequilibrium that has had a central role in macroeconomic theory since Keynes." - R. E. Hall, Massachusetts Institute of Technology; Journal of Economic Literature, March 1972.