Artur Yusupov’s complete course of chess training stretches to nine volumes, guiding the reader towards a higher chess understanding using carefully selected positions and advice. To make sure that this new knowledge sticks, it is then tested by a selection of puzzles. The course is structured in three series with three levels. The Fundamentals level is the easiest one, Beyond the Basics is more challenging, and Mastery is quite difficult, even for stronger players. The various topics – Tactics, Strategy, Positional Play, Endgames, Calculating Variations, and Openings – are spread evenly across the nine volumes, giving readers the chance to improve every area as they work through the books. This book is the third volume at the Mastery level.
I really think this was the hardest book in the series even though all 3 green books are supposedly the same level. The entire series is of very high quality but don't neglect playing too! It's easy to just work on these books for years doing nothing else!