Eco-industrial clusters are geographic concentrations of interconnected industries in a specialized field that coordinate to efficiently share resources and information. They have emerged as a central concept to furthering innovation and competitiveness and advancing sustainable development strategies. In developing and developed economies alike, the fostering of industrial clusters has become a focus of regional development, industrial, and environmental policies. This manual describes concrete steps for obtaining relevant eco-industrial cluster information, devising effective strategies, and communicating the resulting knowledge in a responsible way. Through case studies in various countries, the manual demonstrates the strategic importance of eco-industrial clusters in industrial development and summarizes the prerequisites for successful industrial cluster formation as well as operational aspects of eco-industrial clusters. This training manual is a pioneering effort to bridge the gap between policies and practices in the complex and difficult landscape of eco-industrial clusters.