I’ve been slowly working through this (read: REALLY slowly) and have found it to be a wonderful guide to using Zbrush. I know that’s what it’s supposed to be, but it’s a lot more helpful than the previous Zbrush tutorials. Some of the tips and tricks are amazingly helpful, and even working through the most basic exercises has been refreshingly helpful. It’s very well written, flows well from one area to the next, and helpful for building up not only the ‘check out the latest amazing thing’ advanced tutorials, but the basic foundations as well.
I just wanted to mention this, so that people who haven’t yet started working through it might start to. Good stuff.