I've played guitar in bands for 20 years, entirely self taught. I've also have been producing electronic music with Cubase (and other DAWs - Reason/Ableton etc) for well over 10 years. I haven't been able to read music since my very short stint learning trumpet as a 9 year old!
Because of the above I have at least a bit of grounding in music theory, albeit sub-consciously, as well as experience of the alternative to music notation that is used by music software (ie. midi, piano roll, grids etc).
Most other music theory books are likely to rely on the reader's ability to read music, making the subject inpenetrable to self-taught musicians. So, for someone at a similar level to me (I'm sure a couple of years of music experience as opposed to 20 will be enough), this book is fantastic and I couldn't recommend it enough.
I have learnt loads and loads, and understand a hell of a lot more, in just two weeks. It's very well written, clear, concise and holds your hand throughout. It's very well broken down into the different subjects, so once you've read it all (and most likely been overwhelmed - which can't be helped seeing as it's a big subject), you can go back and re-read the sections you are unclear on. I can vouch that re-reading chapters has really worked for me. I am completely unacademic, so if I can get it, then you can too!
My only small gripe is that there is at least one mistake in the exercises at the end of each chapter (I think!), but it's not going to affect my 5/5 rating as it's improved my understanding of music immeasurably.
One last thing in reference to a couple of the lower-rated reviews. This book is not about synthesis and doesn't purport to be. You won't learn about oscillators or using DAWs etc. There are plenty of other books that do that. This is very a particular book that aims to improve the self-taught electronic musician's knowledge of music theory in order to improve their songwriting abilities (whether it's melody, harmony, chords, beats, rhythm, arpeggiation etc). I think it does that well. I found it logically structured, and yes, while it may give you some information that you find irrelevant to your needs, I'm sure there are other musicians that will find this information useful.