The conventional view of sustainable development (SD) is the integration of environmental, social, and economic concerns into all aspects of decision making. All other principles in the SD framework have integrated decision making at their core (Dernbach, 2003; Stoddart, 2011). It is this deeply fixed concept of integration intended to address today's environmental challenges that distinguishes sustainability from other forms of policy. Interdisciplinary strategies and action to promote sustainable solutions can be a daunting task to accomplish for experts from different disciplines because professionals in their specialist field are inclined to conceptualize the problems in very different ways, and use vocabularies that may not be well understood by one another. A common language and structural framework that allows for the sharing of knowledge between the different disciplines, and the transference of understanding to industry is much needed. In recent years, several theoretical concepts and frameworks, in particular, complex systems theory, ecosystem theory and ecosystem based adaptive management have shaped policy and planning for mixed use landscapes and urban territories. Increasingly, solutions to complex socio-economic problems are adopting systemic principles and practices. This module explores three mutually complementary environmental concepts used to inform land-based development and management, and outlines some of the epistemological and practical problems inherent in each. The concepts and principles on which environmentalism, sustainability and circular economy are built are presented as a coherent and unified model that is now emerging as a framework for achieving targets set out under global Sustainable Development Goals.