This readable, well-illustrated text describes the exquisite job that the mammalian ear does in transforming sound into nerve impulses. The reader is led along the same pathway followed by an acoustic signal--from the outer ear, through the middle ear, and into the inner ear where the minuscule vibrations of the sound waves are transformed into nerve impulses. At each stage, the basic mechanisms are described qualitatively in terms of current theory and illustrated with experimental data.