So far in this book you have learned about common and compound intervals and the written notation for a chord. All good information, but a bit dry and removed from music's sensual experience. This section is designed to whet your appetite for "meat and potatoes" or minestrone (as suits your taste).
Though the real wonder begins with progressions and voicings. You are not ready for such a fantastic study yet. You still need to learn about time (Book 3). Take this brief moment as a bridge, enough to raise interest and answer a few questions before Time begins.