In this volume, Robert Morgan traces with great success the picture of the various currents that have characterized the art of music of the twentieth century. The work is organized in three main parts - Beyond the tonality: From 1900 until the First World War; Reconstruction of new systems: The inter-war period; And Innovation and Fragmentation: From World War II to the present. Each part begins with a chapter describing the intellectual and social climate of that moment, providing essential information to understand the transformations that took place in music. In addition, throughout the text, there are analyzes of some works, as well as a great amount of illustrations and musical examples.