Cooperating successfully in complex systems is a key challenge of the 21st century – a challenge we encounter in the global business context and in almost all policy fields. Whether we are looking at airport expansions, health reform, education system reform or public debt reduction, the complexity of such social change processes requires sophisticated interaction between different organisations and institutions in the public and private sectors and in civil society, and often across national borders and between continents. The Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH possesses over 30 years of experience in managing cooperation worldwide. It has now consolidated its comprehensive expertise by publishing this book. The management model Capacity WORKS is designed for everyone actually involved in cooperation: managers, executives, consultants and advisors in business, governance, public administration and the nonprofit sector. It provides a full introduction to the challenges of successful cooperation management, and supplies practitioners with tried and tested approaches. Five success factors (strategy, cooperation, steering structure, processes, and learning & innovation) delineate the various facets that help focus on the objectives and results of complex cooperation systems. The conceptual framework underlying the success factors is clearly set out, and the success factors are supplemented by an extensive toolbox to support practitioners working in these five areas. At the same time the manual gives readers a broad insight into the world of cooperation management for sustainable development. It includes numerous practical examples, proven contexts of application and glimpses into the work of international cooperation. The editor The Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH is a German federal enterprise that supplies workable, sustainable and effective solutions to political and economic challenges by facilitating social change processes. GIZ operates in over 130 countries worldwide.