In today's sick world, the application of psychological research and methods to issues about and around health could not be more important. Health psychologists pursue ambitious goals, including: the promotion and maintenance of health; the prevention and management of illness; the improvement of healthcare systems; and the formulation of rational health policies. And they seek to understand dizzyingly difficult questions, such as: how do people adapt to chronic illness? What factors influence healthy eating? How is stress linked to heart disease? And, why do so many patients ignore...