Nimzovich covers Centralization, Restraint and Blockade, Over-Protection and Other Forms of Prophylaxis,The Isolated Queen Pawn and the Two Hanging Pawns; the Two Bishops. Alternating Maneuvers Against Enemy Weaknesses When Possessing an Advantage in Space and Forays Through the Old and New Lands of Hypermodern Chess.
All of these strategies are shown by using Nimzowitsch's games with his ideas embedded in the annotations. There over 109 complete games with a lot of other fragments that he played against Tarrasch, Chigorin, Maroczy, Reti, Alekhine, Capablanca, Rubinstein, Spielman, Bogoljubow, and, also, lesser lights.
One thing I noticed about the games is that the themes the games are supposed to represent are not always so clear cut as the examples he used in My System, but that is not really surprising; often in real life things are not so simple.
The chapter on isolated and hanging pawns alone is worth the price of the book. It almost makes you want to play all your games with hanging or isolated d-Pawns! There's a danger in this though. Years ago I read Pachman's Modern Chess Strategy and after thoroughly digesting the book, in my first tournament game I was enamored with the idea of gaining a N outpost. I succeeded in getting it to a fine square on the Q-side and was very pleased with the outcome of my strategy. Unfortunately, I had neglected what my opponent was doing and after plunking my N on the unassailable c5 square from where it influenced the center and dominated the Q-side, I realized that my opponent had been setting up a winning attack on the other side of the board and I was facing a mating attack. It was a painful, but valuable lesson.
In addition to being a nice collection of Nimzovich's games, Chess Praxis is also an excellent book on strategy. One thing often neglected in instructional books (and opening books) is complete games. It's helpful to observe how winning positions are achieved and how the winning positions need to be followed up to the conclusion. It does most of us no good to be shown a game fragment and be told one side is winning; we need to be shown how it was achieved and the conclusion. Nimzovich accomplishes this by using a lot of endgames and late middlegames. For some that my be boring because the exciting moment has come and gone, but think about how many times we non-masters have achieved a won position or played a nice combination but then don't have the slightest idea of how to follow it up and administer the coup de grace.
Another thing I really liked about this book is that, unlike many of today's books, there's not pages of computer generated analysis that nobody plays through anyway; his notes are short and to the point plus there are many narrative discussions where he verbally describes what's going on in a clear, concise manner.
If you can get a basic understanding of positional play, you'll avoid a lot of tactical mistakes because your position is sound...generally speaking, that is. There are positions where you have all the positional advantages but an unnoticed weakness allows a sound tactic. By introducing yourself to the nuances of chess strategy you can't help but improve your game.
Recommended for those beyond the beginner stage and below master. That said, even if you just play over the games by Nimzovich you can't help but absorb something from his notes.