First published in 1977. The volume of research on nonhuman primates has expanded tremendously during the past 20 years and researchers' familiarity with them has increased correspondingly. This series of volumes deals with scientific studies of the behavior of nonhuman primates-apes, monkeys, and prosimians. The behavior of these animals is, of course, of interest in its own right. But, then, so is that of the many other orders of animals. Behavior of nonhuman primates is of special interest because these animals are more closely related to human beings structurally, physiologically, and, beyond doubt, behaviorally, than are any other living animals.