This paper is a comprehensive review of auditory theory and research that bear directly or indirectly on pitch perception. It considers pitch perception from three major points of view. First, it reviews the history of pitch-perception studies and describes some representative theories of hearing they have " engendered. Second, this paper examines various auditory phenomena in the light of how well the different theoretical positions can explain them. Finally, it attempts to collate physiological and anatomical findings about the auditory nervous system and, again, use the facts which emerge to test the adequacy of theoretical concepts and explanations. The 213 references include studies of both humans and animals.