In recent years, the need to address social and environmental challenges has grown in urgency. Climate change, global health, food security and many other global challenges cross national borders and affect a wide range of actors. Yet, in most cases, single governments cannot provide effective solutions. Global challenges call for co-operation on a global scale to build capacity in science, technology and innovation (STI) at both national and international levels. How can international co-operation in STI be scaled up and its scope broadened? How do different modes of governance of international co-operation in STI function and which modes lead to effective and efficient collaboration? Based on case studies, this book presents lessons and good practices on a range of governance mechanisms used for international co-operation in STI to address global challenges. The studies cover organisations that address global challenges including agriculture, food security, health, energy and climate change as well as organisations that bring together various types of actors. It takes a first step towards understanding the complexity of governance of international STI collaboration and provides the basis for future research.