The second edition of Mastery of Music Theory, Book 3 covers the concepts of chromatic harmonization including voice leading, chord progression, and analysis. This edition includes expanded content on introductory topics from the beginning of the 20th century. The format is presented as a text and workbook, providing clear explanations and examples of important concepts while also including worksheets that can be used for practice as well as homework assignments. The books are suitable for classroom use as well as independent learning. Content includes seventh chords, secondary dominants, secondary diminished chords, modulation, Neapolitan chords, and Augmented 6 chords.