In 1978 Hans Cousto, a Swiss mathematician and musicologist discovered the natural formula of the "Cosmic Octave" as the link between different kinds of perodically occurring natural phenomena, such as the orbit of the planets, the weather, colors, rhythms and tones. This extraordinary book explains these relationships with examples of astronomical data comparing the frequencies of planatery orbits, in architectural works, in ancient and modern measuring systems, the human body, music and medicine. Cousto reveals how music is truly the language of the cosmos and of the natural world.