Tactics books

PCfK is a must-have for young players developing their tactical skills, but it should be a part of a broader training regimen because openings and endgames are ignored almost entirely. Of course, this is intentional (focus on tactics), but players who use this as their solely resource may develop "imbalanced skills", that is, strong in tactics but weak in strategical or technical phases of the game. So I suggest to use the series as a "supplemental resource" rather than a comprehensive chess course. The books are excellent at explaining concepts, but they lack of puzzles and exercises for readers to practice on their own, and this limits their utility as a self-study tool. Ciao