Like speech, the species-specific vocalizations or calls of non-human primates mediate social interactions, convey important emotional information, and in some cases refer to objects and events in the caller's environment. These functional similarities suggest that the selective pressures which shaped primate vocal communication are similar to those that influenced the evolution of human speech. As such, investigating the perception and production of vocalizations in extant non-human primates provides one avenue for understanding the neural mechanisms of speech and for illuminating the substrates underlying the evolution of human language. This book brings together the knowledge of world experts on different aspects of primate auditory function. It is likely to yield the richest understanding of the acoustic and neural bases of primate audition and possibly shed light on the evolutionary precursors to speech.