Mindfulness- and acceptance-based approaches such as Acceptance and Commitment Therapy (ACT) and Mindfulness Acceptance Commitment (MAC) are gaining momentum with sport psychology practitioners who work to support elite athletes. These acceptance-based, or third wave, cognitive behavioral approaches in sport psychology highlight that thought suppression and control techniques can trigger a metacognitive scanning process, and that excessive cognitive activity and task-irrelevant focus (self-focused attention such as trying to change thoughts) disrupts performance. Using this perspective, the aim of sport psychology interventions is not to help the athletes engage in the futile task of managing and controlling internal life. Rather, it suggests that sport psychology practitioners should work to increase athletes' willingness to accept negative thoughts and emotions in pursuit of valued ends. Key aspects of such interventions include: teaching athletes to open up and accept, teaching athletes to mindfully engage in the present moment, and helping athletes formulate the values and engage in committed actions towards these values. The goal of Mindfulness and Acceptance in Sport: How to Help Athletes Perform and Thrive under Pressure then is to provide students, researchers, practitioners, and coaches of sport psychology with practical guidance for implementing mindfulness and acceptance approaches in their work with athletes. This book brings together highly experienced practitioners and shares their working methods, exercises, and cases to inspire the sport psychology profession.