As a ski & snowboard instructor myself, I can confirm that this book includes all the concepts & movements that are critical to be a better skier and snowboarder.
The authors did a great job compiling all the concepts in such a compact, handy book. Each concept is first summarized in a sentence and then there are a brief paragraph and a picture associated to explain and visualize the concept. Don't get fooled by the size of the book because each movement might take you years of practice with good coaches to perfect it.
However, this is NOT a "how-to" book! It is best used as a refresher for what your instructors have taught you last season or this morning. Read the book once before your ski trips and review it again after each day of skiing.
Another positive aspect of the book is that it covers other snow toys, such as snow-bikes and snowblades, which are fun and gaining popularity in many resorts but no formal instruction is available.
Overall, this is an excellent handbook for anyone who enjoy snowsports, from beginners to experts, students to instructors.