“Theory is a six-letter dirty word to most musicians, but hey, musicians love dirty words, right? And just like all the other dirty words, theory is easy to learn and fun to use!” MusicScalesChordsMusic TheoryHack Music Theory Book:Hack Music Theory, Part 1: Learn Scales & Chords in 30 minutes Source: Hack Music Theory, Part 1: Learn Scales & Chords in 30 minutes