The last book my Raetsky & Chetverik that I read was a shallow Starting-Out book on the Ben-Oni.
I was concerned this book would be the same. However, it is very different. "The Catalan" is an in-depth book, full of words and wisdom. The amount of variations are just right for a player of my level (2000), and the strategical motifs are well explained.
The book consists of sample games, 95 games on the 190 pages. For each new chapter there is a brief introduction and afterwards a brief summary. The games are analyzed to the end which I think is very important and too often ignored, and they are also full length games with endgames. Evaluation of positions is done with words rather than Informator-style, which I think every book below grandmaster should do. All in all, what better way is there to learn?
The Catalan is quite a beautiful opening. It has the deep strategical idea to make some fundamentally good moves, and enter into a comfortable endgame. Such a way of playing is not to everyones taste, but I think that anyone who enjoyes to play with the king's bishop fianchetto can appreciate it. As the authors say in the beginning: "Between the authors there exists almost a lifetime of dedication to the Catalan Opening. This positionally oriented opening fits our classical style perfectly and has brought us much pleasure in our chess careers."
A review by a writer on another site suggested the level for this book is 2200+. I disagree. Not only do i think 2000 is sufficient, I also think that anyone with an interest in these type of positions will be happy to read the book and benefit from it.
Still, the Catalan can also be used for more aggressive play, if the position allows it.
I think it is very telling that the authors know what they write about very well. The main variations always gets the most coverage, and no important side variations are ignored. Important games are included, as far as I can tell. The players are usually strong GMs, from Alekhine to Kramnik.
Another thing I value very much is that the book doesn't take sides. It does not pretend to give the reader a way to play with either side that is safe, easy to learn, fun, and a real killer (strangely, many books are written like that). I estimate the win ration of the included games to be 50 (white) -30 (draws) -20 (black), quite normal.
There are hardly any books on the Catalan out there. That may be a main reason to give this book the highest grade of 5 stars, since it is probably the best one currently.