"A Life Worth Living" brings together the latest thought on Positive Psychology from an international cast of scholars. It includes historical, philosophical, and empirical reviews of what psychologists have found to matter for personal happiness and well-being. The contributions to this volume agree on principles of optimal development that start from purely material and selfish concerns, but then lead to ever broader circles of responsibility embracing the goals of others and the well-being of the environment; on the importance of spirituality; on the development of strengths specific to the individual. Rather than material success, popularity, or power, the investigations reported in this volume suggest that personally constructed goals, intrinsic motivation, and a sense of autonomy are much more important. The chapters indicate that hardship and suffering do not necessarily make us unhappy, and they suggest therapeutical implications for improving the quality of life. Specific topics covered include the formation of optimal childhood values and habits as well as a new perspective on aging. This volume provides a powerful counterpoint to a mistakenly reductionist psychology. They show that subjective experience can be studied scientifically and measured accurately. They highlight the potentiality for autonomy and freedom that is among the most precious elements of the human condition. Moreover, they make a convincing case for the importance of subjective phenomena, which often affect happiness more than external, material conditions. After long decades during which psychologists seemed to have forgotten that misery is not the only option, the blossoming of Positive Psychology promises a better understanding of what a vigorous, meaningful life may consist of.