In 2010, the Centre for Agroecology and Food Security (CAFS) was established to undertake applied research and education on agroecology as the underlying paradigm of sustainable agriculture. This approach is required not only to ensure that all the peoples of the world are fed, but also for humanity to avoid destroying the life support system and renewable resources upon which it depends. Whilst the term ‘agroecology’ has been increasingly used in international circles over the past two decades, it is less used and not well-understood in the UK, even within the alternative agricultural movements. Therefore this discussion paper was written to inform not only the CAFS multidisciplinary team, but also the very broad audience of people and organisations working for change in the farming production, research and policy arenas. The discussion paper is based on an extensive literature review undertaken by researcher Marco Wibbelmann, and includes contributions by other staff and affiliates of CAFS. It was edited by Karen Brock of Green Ink. Readers are encouraged to quote or reproduce material from this discussion paper in their own publications. In return, CAFS asks for due acknowledgement.