As a musician who's spent years playing by ear, I picked up Mark Harrison's Contemporary Music Theory series to finally understand the 'why' behind chord progressions. Level Three delivers—but with a laser focus that might leave you craving more.

The Good: This book is a masterclass in chord extensions. Want to voice a major-7 chord using Lydian mode notes? Harrison breaks it down with military precision. The exercises + answer keys are golden for self-learners (no more guessing if you're 'right'). After finishing, I could suddenly reharmonize pop songs with jazz voicings—mind blown!

The Frustrating: It's like eating only steak for every meal. Chapters 4-12 obsess over chord extensions while ignoring melody writing, blues theory, or even basic song forms. Where's the I-V-vi-IV analysis promised for pop musicians? The abrupt end left me scrambling for other books to fill gaps.

Pro Tip: Pair this with Novello's The Contemporary Keyboardist for technique—Harrison's fingerings can feel like solving a Rubik's Cube mid-solo.

Final Verdict: 4/5 stars. Essential for jazz pianists diving deep into harmony, but casual musicians might find it imbalanced compared to Levels 1-2.