As real and undeniable as our callousness is, also real and undeniable is our ability to care for and help family, friends, even total strangers. Indeed, most observers find it easier to explain our callousness than our compassion. . . . The latter seems to challenge the truism of self-interest, forcing us to ask: Could it be that we are capable of having another person's welfare as an ultimate goal, that not all of our efforts are directed toward looking out for Number One? This is the altruism question. It is the question that this book attempts to answer.Traditionally, philosophers are the ones who have offered answers to the altruism question. . . . But my [the author's] approach is social psychological, because I think social psychology is the scientific subdiscipline best suited to provide an answer to the altruism question. At the same time, I have tried to write not only for social psychologists but also for other psychologists, philosophers, and biologists. I have also tried to write for students, both undergraduate and graduate—indeed, for anyone interested in the question of why we help one another.