The 164 page book begins by introducing notes, and moves quickly into scales, chords, keys, key signatures and intervals. Also included are modes, ear-training, figuring out music by ear, chord substitution, transposition, improvisation, and song forms.

Written to be read and understood by practical people: singers and players of all instruments (even those who don't read music),  the book shows that learning theory is a very practical thing to do. The book's informal, friendly tone sets it apart from most textbooks, making music theory inviting. Lively illustrations by artist Peter Reynolds complete the effect. A glossary, index, answer section, and copious workbook exercises, charts, diagrams, notation examples.

Here's a more detailed list of included topics:
- Scales: major and all minor scales, natural and artificial modes, pentatonic, blues, diminished, whole-tone and hybrid scales
- Chords: triads through thirteenths
- Quick guide to legible manuscript
- Twelve bar blues forms
- Diatonic and chromatic (including tritone) chord substitution
- Intervallic and chordal ear training
- Interval and chord inversion
- The circle of fifths
- Chord functions
- Secondary dominants
- Transposition
- Cadences