As someone who's spent years playing by ear, Mark Harrison's Contemporary Music Theory series has been a game-changer for me. Level Three feels like unlocking a secret jazz pianist's handbook—but be warned, it's laser-focused on chord extensions to the point of obsession.

The first two chapters lull you into thinking this will be another well-rounded theory book, then BAM—you're suddenly immersed in nine straight chapters dissecting every possible chord voicing. I now dream in major-7 Lydian extensions and can harmonize melodies in my sleep. That part? Absolutely brilliant.

What frustrates me is what's missing. After the fantastic breadth of Levels 1-2, hitting this hyper-specific chord wall feels like getting a masterclass in tree bark when you expected the whole forest. Where's the pop progression analysis? Blues theory? The I-V-vi-IV that dominates actual pop music?

The exercises with immediate answer keys remain gold—I've filled two notebooks working through them at my piano each morning with coffee. But that nagging feeling persists: this should've been marketed as 'Advanced Chord Extensions Method' rather than the grand finale of a comprehensive theory series.

For jazz pianists wanting to geek out on voicings, it's five stars. For everyone else? Amazing knowledge wrapped in disappointing packaging.