In those 100 years, in the acoustic universe, many more things have happened than in the whole history of the music. New genres, new forms, new technologies, new ways of thinking music have contributed to the most dense period of sound miracles: the noises, the dodecaphony, the electronics. Composing a canon of masterpieces of cultivated music of the 1900s means, first of all, providing a guide to get oriented in a century that has produced marvelous works, but also delineating the story and the path of a sound that has changed, has taken new directions and often went back on his steps. 100 short chapters, each with an essential discography, for 100 songs that outlined the twentieth century sound landscape.