Sharpen Your Tactics! 1125 Brilliant Sacrifices, Combinations, and Studies, by Anatoly Lein and Boris Archangelsky

Sharpen Your Tactics is a workbook of 1125 positions to solve, many of which are apparently from the personal collections of the authors and had “never previously (been) published in the West.” The problems start out very basic (e.g. mate in 1s) but gradually get more and more difficult, with the penultimate exercises being difficult enough to challenge masters.

As explained in the foreword, many different levels of players can improve their chess by a rigorous study of these challenging puzzles, but I think players in a USCF rating range of 1700 to 2100 would see the most effect. Lower rated players could also benefit by starting out with some of the easier problems, and working their way through the rest of the book as their overall skill improves.

The book is in close to new condition, with only minimal signs of age and no markings.