This book is a theoretical investigation of the influence of human learning on the development through time of a 'pure labour' economy. The theory proposed is a simple one, but aims to grasp the essential features of all industrial economies. Economists have long known that two basic phenomena lie at the root of long-term economic movements in industrial societies: capital accumulation and technical progress. Attention has been concentrated on the former. In this book, by contrast, technical progress is assigned the central role. Within a multi-sector framework, the author examines the structural dynamics of prices, production and employment (implied by differentiated rates of productivity growth and expansion of demand) against a background of 'natural' relations. He also considers a number of institutional problems. Institutional and social learning, know-how, and the diffusion of knowledge emerge as the decisive factors accounting for the success and failure of industrial societies.