I got the whole collection, and each lesson 1-16 is different songs. But to make it really effective, Hanon breaks down the most important changes in the songs as a mini-progression, and asks that you learn it in all keys. Once you learn the mini progression in all keys, you'll start hearing songs with that particualr progression in there, and easily be able to thrwo it in, because you already know it. Then its easy to also spice up your arrangements, with these progressions to, because you can hear where it would fit in other songs. That minor ii-v progression opened my ears up so much. I would always miss that change in picking up a song, now I got it.