How do we change behaviour? This is a key question for anyone trying to promote health and wellbeing. It is also important for us, as individuals, as we strive to lead healthier lives. From wearing a face mask to taking up more exercise, behaviour change is vital to improving and protecting our health. This textbook offers a fresh approach to health psychology through the theory and practice of behaviour change. Using an array of case studies from around the world, it discusses how we can develop and evaluate behaviour change interventions. The book encourages active engagement with contemporary discussions about health behaviours, covering areas of emerging importance such as weight stigma, vaping, nudges, vaccine hesitancy and paleo-inspired lifestyles.