This is a practical guide to designing and evaluating behaviour change interventions and policies. It is based on the Behaviour Change Wheel, a synthesis of 19 behaviour change frameworks that draw on a wide range of disciplines and approaches. The guide is for policy makers, practitioners, intervention designers and researchers and introduces a systematic, theory-based method, key concepts and practical tasks. 'The Behaviour Change Wheel - A Guide to Designing Interventions' brings together theory-based tools developed in behavioural science to understand and change behaviour to form a step-by-step intervention design manual. This book is for anyone with an interest in changing behaviour regardless of whether they have a background in behavioural science. Authors, Professor Susan Michie - a world authority on behaviour change, DR Lou Atkins - researcher and Associate Teaching Fellow at the University College London's (UCL) Centre for Behaviour Change, and Professor Robert West - an internationally renowned expert on smoking and addiction, guide you through each step.