Ive studied music books and even went to music school but the way this app describes and illustrates music theory is more clear and concise than any of the above. I have a very analytical mind and have a tuff tough time just accepting that "this pattern is this way and thats how it is" (granted you learn later why) from other resources. This app presents the why from the start without overwhelming you because of its amazingly simple illustrations. But it!! Youll learn more than you will from a $20 book
Wifiquester about Music Theory by Musicopoulos, v2.6.1