Master Your Technique, by FM Thomas Wolski.
This module contains 50 rich and thoroughly analyzed challenges. The majority of these challenges focus on complex middlegame positions, the art of transition from the middlegame to the ending, and on endings themselves. This module is aimed at all players from the intermediate level (about 1400) to strong masters. Experts and Masters (FIDE and USCF Ratings over 2000) will not find these challenges easy. Many of the challenges will be hard for the intermediate player, but they will learn a bit more with each attempt until they become a master of technique. The challenges feature an average length of 10 moves.