Book excerpt: The authors in this book regard the process of economic expansion as a non-homogeneous and multifaceted phenomenon which has deeply affected human welfare, and cultural, social and political change. The book is a bridge between the theorists (Rosenstein-Rodan, Lewis, Myrdal, and Hirschmann) who in the post-war period analyzed regional inequalities, structural change and dualism, and the modern literature on economic growth. The latter has emphasized the existence of multiple equilibria, bifurcations and various types of dynamic complexity, and clarified the conditions for the emergence of phenomena such as cumulative causation, path dependence and hysteresis. These are the typical ingredients of structural change, economic development or underdevelopment.