It has been around for a few years, but if there is one book we'd recommend reading it is Music Theory for Computer Musicians. It’s a great book that tells you everything you always wanted to know about Music Theory.
There’s something in this book for everyone. From the characteristics and properties of sound to topics like notes, scales, chords, rythm, tempo and note lengths, melodies and motives, the author dedicates plenty of pages to explain every aspect in a concise and clear way.
It is not necessary to have a grasp of music theory to compose cool music. Plenty of producers create awesome music without a clue. However, having a basic (or more in-depth) understanding of music theory definitely helps! This book can be your essential guide.
You can buy the book on Amazon.com here.