This chapter explores the application of complex systems theory to understand the rapid growth of international collaboration in science and technology, particularly as it can be applied to global challenges. The global system operates like a network, and, as such, it can be understood and governed by applying network measures. This approach is a departure from earlier public policy models, which used national boundaries and organizational themes to craft policy recommendations. Accepting that the global network of scientific collaboration is an emergent system, we can begin to develop concepts around it as an organization. This is approached as a nested heterarchy (tangled composite structures) with feedback loops. The challenge for governments is ensuring that the local loop does not disengage from the heterarchy.