Vol. 4 seems like a big step up from Vol.3. It's a challenge but that's what you want. There a fewer pieces than in Vol. 3 but that maybe because they'll need more work on each. It begins with a piece much longer than in the previous editions - it's four pages long - a nice challenge. It also introduces the tenor clef in the last piece - another nice challenge. There is also a more challenging use of bowing and timing.
There is large number of scales at the back - both major and melodic minor - and a few tenor clef exercises. I'm enjoying it.
- (Richmond, United Kingdom)