This is definitely a textbook. It doesn't address fitting, or sewing techniques, or anything but flat pattern design.
Essentially, you make a sloper and then practice lots of techniques to alter it. After reading (and practicing) these techniques, you will be able to move and alter darts like a BOSS!
You'll also learn something about altering necklines and sleeves, and there's a tiny bit about skirts and pants (the section on pants is wildly out of date and not very useful).
Overall, a useful book. Not great, but quite useful for those of us who want to learn to either design patterns, or learn to alter them.