“Attacking and Defending Moyos”
Volume seven from the "Mastering the Basics" series is a mix of theory, example games and 151 problems.
The theory part contains thirteen principles. Most of them are pretty basic, so i think they won't be a real eye-opener for a single digit kyu.
Example: "Make a deep invasion into your opponent's moyo only if there are defects to exploit"
Easy isn't it?

I think the crucial point is not knowing or not knowing these principles but to have good tactical skills. That's why i think that the usefulness of these principles is very limited.
The principles are also referenced in the comments of the example games and in the solutions to the problems. But not very often.
The commented example games from famous players like Kitani Minoru, Cho Chikun and Takemiya Masaki. The examples cover only the fuseki and middle-game. But that’s enough to appreciate the differences between territory and influence styles. Some of them are a little bit extreme, so i regard them not as educational examples but just as showcase for a particular style.
The format of the problem part is similar to "501 opening problems": Four problems on one page than the solutions diagrams. The solutions for the four problems are usually presented on the next three pages. The solution for some problems is presented with up to four diagrams (one page). That’s much more detailed that in other books from this series. In my opinion this is a big improvement.
The level of difficulty is very different, with a similar spread like in the book "Making good shape". The easy problems can be solved with the principles from the theory part. But the harder problems can only be solved with good tactical skills (especially the knowledge of sabaki and reductions techniques) and a good positional judgment. But these details are worked out very well in the solutions where also false variations are explained, the moves which are "usual" but bad from a global perspective. ( The moves i usually play.

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The problem diagrams have always a little introductory text. But it think that this not such a great disadvantage like in the book “501 opening problems” because you usually cannot get the solution just by identifying the relevant principle, you also have to compare similar variations in detail.
Opinion: The theory part is too specific to provide general advice on how to handle influence and moyos on an advanced level. So don’t expect much from this. Nevertheless this part is much more useful than in the book "Making good shape".
The games are not very educational but quite entertaining.
The problem section is the reason why i like this is a book. Working through the problems is a lot of fun. If you study the solutions carefully you may identify some of your weaknesses in positional judgment.
Here is a sample problem (Nr. 45, one of the easy problems) and the solution (four diagrams in the book):