Of course, in this Theory of Music, you will find all the information that appears in any complete theory, on notation, measure and rhythm, intervals, pitch, etc., but here each chapter is followed by a commentary entitled "To know more", which explains the reasons, historical or technical, which led to the rules and habits currently in force in Western music.
An important appendix deals with subjects that a traditional theory does not usually address, such as Gregorian notation, medieval modality, or new techniques and signs that appeared in the 20th century: diatonic and chromatic modality, dodecaphonic serialism, random music, special notation, encryption of the guitar in jazz. The ensemble is illustrated with numerous examples borrowed from classical or contemporary composers.