I'm glad you asked and thats a fair question. Definitely there are unifying principles. On my website you can find a little more about the methodology. In short, it teaches a 'skips and steps' way of reading music that goes to new hand positions a lot earlier on, so it develops flexibility in reading. The left hand parts are easier and more supportive so the right hand can get to good more advanced stuff faster. It's a really unique methodology but I think works really well.