I picked up this book because I still need to learn some CAD modeling for the 3D printer I just purchased. My free options were OpenSCAD, Blender, or Google/Trimble SketchUp. I know Blender is the most powerful of the bunch so I decided on giving it a try.
The book does a really good job in explaining some basics of how everything is set up on the GUI. It's similar to Photoshop in some ways, which can be useful if you use Photoshop. I haven't so it was nice to have all the explanations in the book.
It also goes through a quick run through of GIMP as that will be useful for fully utilizing Blender.
The rest of the book was pretty good but I ended up quitting half way through as it's better suited for modeling life like models instead of doing models you would normally 3D print. You can definitely print things you come up with in Blender but for my purposes 99% of the time, I wouldn't need something as powerful as Blender. If you want to do animation or life like modeling, Blender is perfect. If you want to do architecture, SketchUp is great. If you want to do basic parametric modeling, OpenSCAD works well.
This book, as far as I made it, did a great job taking you step-by-step through how to make a few different models. The images used were very helpful to know how the modeling works.
Overall, I would recommend this book for those doing life like models or animation. If you're looking for something more like engineering models, you'll be better served using something else.
Disclaimer: This book was received as part of the O'Reilly Blogger Review Program. All comments represent my thoughts and opinions.