Harmony is an integral part of our auditory environment. Resonances characterised by harmonic frequency relationships are found throughout the natural world and harmonic sounds are essential elements of speech, communication and, of course, music. Providing neurophysiological data and theories that are suitable to explain the neural code of pitch and harmony, the author demonstrates that musical pitch is a temporal phenomenon and musical harmony is a mathematical necessity based on neuronal mechanisms. Moreover, he offers new evidence for the role of an auditory time constant for speech and music perception as well as for similar neuronal processing mechanisms of auditory and brain waves. Successfully relating current neurophysiological results to the ancient ideas of Pythagoras, this unique title will appeal to specialists in the fields of neurophysiology, neuroacoustics, linguistics, behavioural biology and musicology as well as to a broader audience interested in the neural basis of music perception.