This collection of original articles reviews the current state of knowledge concerning the convergence hypothesis. This hypothesis asserts that, for a restricted set of countries, their productivity and living standards are undergoing a process that brings them increasingly close to one another. Among the factors considered are patterns of industries as well as aggregate economies, influences that underlie the degree of convergence that seems to have occurred, and the role that convergence plays in the future of the newly developed nations. Much of the analysis is set in historical perspective.