Step by Step Go
Step by Step Go, written by Huang Xiwen 6p and Nie Weiping 9p, consists of 4 books, as well as a problem book series.
The levels described for the books are not quite accurate. The first book may be useful even for stronger dan players, and many sections in the other books are interesting also for single digit kyu players.
Volume 1 (red): Up to amateur 1d, covers
life and death, tesuji, fuseki, joseki, middle game, and endgame
Volume 2 (green): From amateur 1d to amateur 3d, covers
opening, joseki, life and death, middle game tactics, invading and reducing, and endgame
Volume 3 (blue): From amateur 3d to amateur 6d, covers opening, attack and defence in real games, middle game, famous life and death problems, and whole board endgame problems
(ISBN: 7-5381-4089-1)
Volume 4 (orange): from amateur 6d to professional, covers
wholeboard problems from the real games of ancient chinese players, modern chinese players, ancient japanese players, modern japanese players, and korean players