As I own a Music Academy, at any time we have 5-10 Piano instructors, and yes we talk about books and lesson plans. As my daughter was in lessons with one of our instructors, we had many conversations about different books, as a parent, I can see that because of the way it is written for children, it is a really nice entertaining book and Alfred has these books concentrating on Level 1 & 2 then up to Level 6. Most of the time the first two levels are split into a few volumes, while the latter are single volumes, all worth getting in order, of course.
For Adults…. Wait it's a children's book??? Exctly and what we have really come across, as I started taking lessons with the instructors at our academy and of course, I have the adult book, but being a guitarist, this is a new instrument for me.
As was explained and is true, the children's book takes a much longer span to cover more material, while the adult book does not. What this means is that the adult book may concentrate on fingering for a page or so and then assume, you have it down and jump to the next step. The children's book does not do this it spends more time and creates more of a solid base for you as a child or adult.
So don't be as fast as I was to get the adult book, until you've spent some time with these.
Average price range should be from $6-10 each book.
Hope the review helps shed some light and understanding, it's a great book throughout all the levels and add-ons.