Herman Grooten
Chess Strategy for Club Players
The subtitle "The Road to Positional Advantage" perfectly describes what this book is about. Learn positional play and how to come up with ideas in the middle game.
Etiquettes:
Positional Chess
Recommendations
My all time recommendation for club players on positional chess is a book called "Chess Strategy for Club Players" by Herman Grooten. It is a full compendium of positional concepts.