This PhD programme has emerged in response to the global challenge of sustainability and the need for transdisciplinary knowledge of complex social-ecological systems. Solutions to complex sustainability challenges cannot be found by only adhering to and using the traditional set of disciplines that determine the domain and method of scientific inquiry and upon which the structure and purpose of university departments and faculties are based. A transdisciplinary challenge requires a transdisciplinary response. This means that in order to understand and respond to the sustainability challenges, we need new ways of knowing and producing knowledge that make it possible to develop an integrated understanding of all the interacting systems, in particular inter-related natural and social systems. The challenge of sustainability is not simply about bringing together different disciplines across the disciplinary divide. It is also about going beyond disciplinary boundaries, engaging with societal actors, changing and extending our understanding of knowledge production, and what we mean when we claim that we have knowledge about a particular system or cluster of inter-connected systems of which we are integrally a part.