Based on case studies from Brazil, Vietnam, Indonesia and India, this volume examines SME clusters and argues that unless they counteract common problems such as very low wages, poor working conditions, poor quality products and lack or environmental regulation, they will be pushed out of the market and so become unsustainable. It puts forward conceptual frameworks which explain the way firms can upgrade: through markets, interaction among cluster members, through Corporate Social Responsibility and other such public policy, and through the better enforcement of regulation.