I just purchased his first book on the QGD. It looks like the second and third books have far less words... are they much more skeletal (and therefore geared to more advanced players) than the first one that he just revamped and added words to?
How to play with black against everything but 1.e4

I just purchased his first book on the QGD. It looks like the second and third books have far less words... are they much more skeletal (and therefore geared to more advanced players) than the first one that he just revamped and added words to? You are right, less words. I think the students should just ask questions the author in the positions, and slowly we will have enough explanations in those books too. This is the advantage of Chessable, the books can be something very organic, growing through the collaboration between us and the authors.
I would like to introduce here succinctly three repertoire books written by the GM Alex Colovic. Some of you know Alex already from his great articles in chess.com. https://www.chess.com/blog/alexcolovic/berlin-candidates-2018-round-9
https://www.chess.com/blog/alexcolovic/berlin-candidates-2018-round-8
Here is an interview with Colovic
https://soundcloud.com/ethan-paz1/alex-colovic-interview?utm_source=soundcloud&utm_campaign=share&utm_medium=twitter
(In this interview he says that he got a GM basically solving tactics at least one hour per day, every day. He says that if somebody has zero talent but work really hard he can get a FIDE master, and with some talent there is possible to get a GM if somebody really work very hard to reach this goal.)
The books were published in chessable.com, a website which allow the students to learn repertoires, endgames, and tactics by spaced repetition. This is what you can read about spaced repetition in the website:
"The spacing effect or spaced repetition theory began with research in the 19th century. In a nutshell, you learn best when you review your knowledge in increasing time increments rather than regularly. At Chessable, we provide a scheduling mechanism that prompts you to review material in an efficient manner. Get the chess move right, and you won't see it for a while. Get it wrong, and we know it needs some work so you will see it again soon. Can it get more efficient than this? We think not!"
"Researchers found concrete evidence showing how dopamine can improve learning. When dopamine is released, learning is enhanced. Chessable is set up in the form of a game. You are provided with rewards such as points, badges, titles and many other fun things. Being set up as a game allows us to tap into the effect games have on dopamine and, therefore, enhance learning. So while using Chessable, your brain should be releasing more dopamine than it would if you were to study from a book."
There is a rather known and ambitious chess.com-player who wrote a useful review about learning endgames in Chessable https://www.chess.com/blog/Milliern/review-chessable
Okay, let's come back to the books by Alex Colovic available in Chessable that I am studying. They are following:
"Queen's Gambit Declined: A Grandmaster Explains"
"A Grandmaster Guide: The Reti, King's Indian Attack, and others, based on the QGD"
"On the Way to the Queen's Gambit Declined"
I began to learn the Queen's Gambit with other authors. However, after I began to learn in Chessable I decided to purchase the repertoire by Alex Colovic. I had several reasons for this decision. On the one hand, Colovic gives with his three books a full repertoire for black against everything but 1.e4. For example, he also gives lines against dubious things like the Grob, which you will not find in may books (but when you face this kind of stuff OTB for the first time you will really wish you would have at least an idea how to deal with this).
On the other hand, Colovic's explanations are very detailed. He tries to explain the ideas behind most moves which are not so obvious. If you have problems with certain moves, you can ask him and usually he will answer you between 10 minutes and 24 hours. I don't remember one single time he did not answer one of my questions (and I asked A LOT of questions over the time).
There is a reason for this huge amount of explanations. The first book by Colovic was initially known as "A Grandmaster Guide to the Queen's Gambit Declined". It was initially aimed at advanced players. However, in Chessable you have a large number of ambitious casual players and beginners which were interested in this book. To make his book readable other players, Colovic did a major update of an extra 13,000 words of instruction, explaining the lines in a way that even post-beginner would be able to follow. With the time, students of this book asked several questions about moves that they didn't understand, and the answers to this questions are available to all students. (This is a cool thing about Chessable: the books published there are not finish, as they will grow organically in the interaction between students and the authors - a thing that is simply impossible in other kind of chess books.) And finally, Colovic decided to publish two further books to cover other lines beside 1.d4 d5.
There is an additional factor of his books that make them very attractive for me. Colovic give us a repertoire that he used his own preparation to create it. In his own words:
"It is a no-holds-barred revelation of my preparation, something I have never done before, and especially not with an opening I still actively use. My only hope now is that the people who take upon this repertoire will not be the people I will get to meet across the board!"
I am writing this review to express my gratitude to Alex Colovic for his patience in answering my questions. Thanks Alex, and I hope other people will begin to work with your repertoire!
At the end check this game Colovic vs. Brochet in 2013
http://www.alexcolovic.com/category/my-tournaments/