I love solving exercises for training purposes and pure enjoyment, and I own nearly a dozen books devoted to tactical chess. So, I really needed a compelling reason to buy another tactics book. I found Nunn's treatment of tactics to be different in that Nunn's focus is on evaluation of a position, calculating and analyzing, rather than simply finding the "brilliant" or trick move that forces a mate. In other words, unlike beginner tactics books (say, Reinfeld's 1001) where there are hundreds of queen sacrifices forcing mate, Nunn's examples are more pragmatic and needing of careful calculation. Of interest is Nunn's background info on tournaments of the past - so we aren't simply solving problems out-of-context - which is fascinating. If you're a player, rated 1400-2100, you'll probably find this book extremely useful for long-term problem solving abilities. Other good books on this subject include "The Best Move" by V. Hort and Jansa, and "Test Your Tactical Ability" by Y. Neishtadt.