Plomp's —published 25 years ago—dealt with the psychophysics of simple and complex tones. Since that time, auditory perception as a field of study has undergone a radical metamorphosis. Technical and methodological innovations, as well as a considerable increase in attention to the various aspects of auditory experience, have changed the picture profoundly. This book is an attempt to account for this development by giving a comprehensive survey of the present state of the art as a whole. Perceptual aspects of hearing, particularly of understanding speech as the main auditory input signal, are thoroughly reviewed.