If you want to gain a more in depth understanding of music theory, this book is a good place to start. This book covers scales, intervals, notation, tempos, chords, melodies and much more, and is written in an easy to understand format.

This practical, easy-to-use, self-study course is perfect for all musicians, composers and arrangers. 75 lessons over 18 units conclude with  question and answer sections. Comes with a CD.