This book compiles research evidence and clinical perspectives on the benefits and pitfalls of exercise in rehabilitation and recovery from illness or injury. The content focuses on the growing and important concept of increasing physical activity in people with long-term health conditions, maintaining active lifestyles for physical health and well-being, prevention of secondary illness and recovery from injury. Furthermore, whilst it is known that exercise can help aid recovery from many illnesses and injuries, maintaining a physically active lifestyle is vital in the prevention of a wide range of life-threatening diseases. Therefore, encouragement of exercise participation and the integration of physical activity within the daily routine seems an appropriate strategy for everyone. That is, the importance of physical activity in rehabilitation, recovery and secondary prevention, cannot be divorced from the necessity for a population-based strategy of preventative medicine, thus focusing on increasing energy expenditure in the whole population, promoting activity from an early age, and making a resolute difference to population health in future generations.