The extended edition of the book gets even better. The problems are well selected to illustrate various concepts and key ideas in chess, especially combinational vision and intuition. The presentation format is brilliant; for each problem there is a hint at the end of the book, where one could see the difficulty rating of the problem and more importantly there is a small observation of weaknesses in a given position and how one could try to explore them. This makes solving difficult problems more enjoyable, developing a good habit to analyze positions first and then find a plan of action. Hints help also to cope with problems that are slightly beyond the present ability, which is a good way for training. At the very end of the book the full solution is given with one or two diagrams to guide the reader's eye through the tree of key variations. I have a dozen of chess puzzle books, but this one is my absolutely favorite!