The Auditory System in Sleep presents for the first time a view of a sensory system working in a different state-that of the sleeping brain. The auditory system is always “open” receiving information from the environment and the body itself (conscious and unconscious data). Even during sleep the auditory information is processed, although in a different way. This book draws information from evoked potentials, fMRI, PET, SPECT, lesions, etc., together with electrophysiological online data in order to depict how the auditory system single unit activity, recorded during sleep, revealed the possibility of sensory information participation in sleep processes.