Crucial Chess Skills fo the Club Player vol. 1 de Robert Ris
"From all the sorts of activities I keep myself busy with in the chess world (playing, organizing, commentating, writing, teaching etc.) I consider myself mostly a professional chess trainer. The majority of my students are rated somewhere between 1500-2200 and have the ambition of improving their play. I dare to say that players within that range of strength are most likely to learn a thing or two from studying the material in my first book. In any case, it has been my aim presenting the material in such a way that it would be understandable for a broad target group. "