Why do Americans collectively devote 20 billion hours of their time each year to helping others? To find out, Wuthnow (Sociology/Princeton; The Restructuring of American Religion, 1988) surveyed 2110 adults across the land, many of whom provided in- depth interviews; he presents his conclusions in this penetrative, well-written work. Americans, explains Wuthnow, are instinctively uneasy about describing exactly why they perform good deeds. He helps to clarify their motivations with a deft narrative that weaves together the stories of very different types of good Samaritans--from the rescue-squad worker with his ``iceman'' approach to helping others, to the pediatric cardiologist who combines professionalism and empathy as she deals with the bereaved parents of babies she's lost, to the Presbyterian missionary who's inspired by evangelical fervor. Each subject is willing to work through a plurality of motivations to get to the bottom of his or her desire to do good because, according to Wuthnow, ``Motive-talk provides connections with our cultural heritage. It associates us with the various values we have been taught to accord prominence.'' In each case, Wuthnow uncovers a need to reconcile individuality--which he sees as a defining American cultural value--with altruism. The author finds that most Americans, even liberal clerics, prefer to describe their impulse to help others in terms of self-fulfillment rather than theology, and that most ``situationalize'' their stories, focusing on individuals rather than on principles. In spite of what Wuthnow sees as a tendency of Americans to set limits on their caring, a striking 31 percent, he reveals, are involved in ``charity or social-service activities, such as helping the poor, the sick, or the elderly.'' Elegant, illuminating, and of significant interest in this decade of need and limits.