Distinguishing concepts of "worth" and worthiness of human lives and human activities from questions concerning value, well-being, or virtue, Steven G. Smith explores how worthwhile acts implement ideals of worthiness in four major domains--work, play, action in concert, and love. He touches on a wide range of theoretical material, including Western and Eastern philosophy, ancient and contemporary figures, interdisciplinary studies, and literary texts to provide a comprehensive look at how we rely on ideals of worthy action in the pursuit of moral happiness. A concluding chapter considers how the entire system of worth thinking works as a sort of moral economy in which cost-benefit calculations can be made, as a moral politics in which ideals can be asserted and negotiated, and as a religion in which ultimate valuations are anchored.