Book excerpt: Seeking Sustainability in an Age of Complexity explains the difficulties of sustainability and why 'collapse' can occur. In the last twenty years the theory of complexity has been developed - complex systems science (CSS) speaks to natural systems and particularly to ecological, social and economic systems and their interaction. Due to the growing concern over the huge changes occurring in the global environment, such as climate change, deforestation, habitat fragmentation and loss of biodiversity, Graham Harris sets out what has been learned in an attempt to understand the implications of these changes and suggests ways to move forward. This book discusses a number of emerging tools for the management of 'unruly' complexity which facilitate stronger regional dialogues about knowledge and values, which will be of interest to ecologists, sociologists, economists, natural resource managers and scientists in State and local governments and those involved in water and landscape management.