Am quite a fan of the quality chess series of books in general, but personally more the middle game, and game collection ones.  The GM rep books are a bit too variation based, for my level of play, optimistically ~ Fide 2000. They are doing what says on the tin though, i.e designed for upto to GM level, and well I am not a GM,  For the Marin set of three books the disappointment is a bit different though, because in quite a few places think he over sells what has acheived in books in several places. 

One example is below, for the semi-tarrasch like line, sometimes called the Keres-Parma variation. His suggestion is 7Qa4, which doesn't look that great to be honest.

In contrast the much older book "Dynamic English" gives quite nice explanation of ideas in the IQP position after 7NxN pxN 8d4 Be7 90.0 0.0 10 pxc5 Bxp 11Bg5.

Like most repertoire books, many equal lines are overhyped as "advantage x" where X is White in White repertoire books and Black in Black repertoire books.

The writing, layout, and level of explanation is excellent in those 3 books, but the evaluation of some of the lines is overhyped for white.

I also see their GM rep book on the Tarrasch Defense as overhyped on Black equalizing against 6.dxc5!  6.dxc5 is a serious problem in the Tarrasch Defense and after one breath where they acknowledge that this has been a big discovery for White, they brush it off as equal in 2 chapters and I think they overhype Black's position.

I mostly prefer their middlegame books and New in Chess for openings.

The ones that are more middle game themed based on a single opening, like Kings Indian Warfare or Opening Simulator: The Kings Indian are excellent.  But be wiry of GM Repertoire or Playing the series.

Bashing a chess book author for original content is not different from criticizing a fiction writer for telling an unreal story. Chess books are not high-school textbooks; while laws of physics are mostly objective, interpretation of chess positions is not, as is evidenced by the fact that identical chess games are exceptionally rare.

And in this particular case 7.Qa4 is not a bad move at all. Unlike many of Marin's original suggestions, this remains largely untested because ...e6 is far from an appealing option for Black, which blocks the c8-bishop for little reason.

Don't you find 7Qa4 a weird move though? After 7Qa4 Bd7 8Qb3 Nb6 black is threatening Nd4 next, followed by Bc6. Think white chould easily become worse here. 

I have no idea how White could "easily" become worse after 9.O-O Nd4 10.Nxd4 cxd4 11.Nb5 Bc6 12.d3 a6 13.Na3 Bxg2 14.Kxg2. It's Black who has to play with extra care. In the endgame Black will find himself slightly overextended. On the other hand, with queens on board, the b6-knight will feel uncomfortable. White's apparent lack of space means nothing since his development is unhindered.

What's weird with 7.Qa4 ? Using the queen to drive away the d5-knight looks like a perfectly sensible idea. Read the book if you can't even understand this move.

Umm, not very attracted to 7Qa4, and not many players have been to be fair to myself, would much prefer playing black in resulting positions. 

Also e6 isn't has pointless, as seem to be think. Preparing d5 is quite a classical way of playing. Even nowdays Anand, and Nepomniachtchi play these semi-tarrasch type positions quite a lot. Even after for me,more to the point 70.0 Be7 8d4 it isn't easy for white to get an advantage.

Regarding books personally find Kosten's "Dynamic English" somehow manages to be about 1000 pages less, but gives more to the point explanation. Maybe  that's just me though. 

You would need more than 7 Qa4 Nb6 8. Qe4..after 8...f5, white is on the run.

For example

Just tackling the title of the thread:

GM Tony Kosten, author of one of the best books on the English before Marin's, wrote that he wished he'd written Marin's books. 

Marin's volumes on the English are still state of the art. One could play his repertoire for life as a strong master and score very well. I'm sure there are some weaknesses, but overall it's an excellent repertoire series. 

Regarding 7.Qa4!?

Alexander Khalifman addresses one of White's problems in his Opening For White According to Kramnik volume 2 (2001). He argues that Black's move order makes 7.d4 slightly dubious because it allows Black to transpose into other lines that grant equality to the second player. Khalifman recommends 7.0-0 because 7...Nf6?! is "notorious" due to a line played by Uhlmann and Korchnoi back in 1981. 7...Nc7?! is also dubious according th Khalifman. 7...Nb6 is considered more complex but Khalifman gives White a path to an advantage there too. That leaves the main line stuff of 7...Be7.

Khalifman's solution is played in the vast majority of modern GM games as far as I can tell.

Marin's solution of 7.Qa4 looks a bit weird by comparison, but it is almost certainly in answer to the same problem that Khalifiman noted. White's score with 7.Qa4 is quite impressive, but it hasn't been tried much since the 1980s. 

You may be right, @TwoMove, that it doesn't hold up particularly well these days. I might be able to find out if he still recommends it or suggests another plan now. 

Always fantastic how amateurs who are ignorant can make judgement about GM's works.

Anybody can give bad lines, but Marin's books on english are known for one of the best works (the best?) on English opening.

U don't like the line? Well pick another, u have still many pages with high level for you.

White is not forced to play a stupid queen move like Qh4?

In your line on move 9 @nighteyes1234

 Black is playing for a center bind and so Qe4 is dubious off the bat. So I disagree with poucin about it being a one off glitch due to engines busting pretty good moves. Its more of a win with accelerated dragon logic that has people thinking black has an advantage in it.

Even chess.com Stockfish can play out the rest of the moves that are alternates.

I don't have the book in front of me, but one chapter of Volume 2 covers 1. c4 b6. In one of the lines Marin shows the moves through whites 17th and then states that white has a stable blockade and a dangerous kingside attack. My complaint is that black had a really strong looking 17th move and I couldn't find a good response for white. I was able to locate the whole game and sure enough, black played the move that concerned me and went on to win. I know it's a book that discusses the opening, but I wish that Marin had at least shown blacks 17th move and suggest whites best response.

Ok but it could have been useful to give the line...

No idea about what you want from a book.

You don't buy Marin's books for the depth of his analysis, but for the good prose, and explanation of ideas.

If you don't like a suggested line, go on and pick one you like better- simple as that.

Thats a bit normal to dislike some lines in a book, so never be surprised to see a line (only one would be fantastic) u don't like or u don't feel playing.

U don't buy a book just randomly.

Some authors are well known for explanations (like Marin). some for deep analysis, original, sound, humorous, etc...

And before purchasing a book, u can read some pages, have a look on reviews...

Marin later produced a chessbase dvd on the semi-tarrasch called "Semi-Tarrasch: A universal weapon vs d4" https://www.youtube.com/watch?v=slkqQjn7qcw.  So maybe he went with the somewhat left field 7Qa4, because he didn't think white had much in the more main-line options either. After 70.0 Be7 8d4 0.0 9e4 he prefers 8...NxN 9pxN pxp 10pxp going into a common semi-tarrasch pawn structure, the most well-known with Bc4 instead. The elite player seem to prefer 8...Nd-b5 with Watson's old suggestion of 9d4xc5 Bxc5 10e5 being explored in several games. 

I am an advanced beginner maybe intermidiate, I would say, and I find his book very instructive. What I like is that he explains the ideas in a very clear way, even for someone my level, and I learned a great thing about chess as well, not just the English opening.

Let's be a little more fair on this

1st-

The move order you gave was a little different, but transposes (e6 before d5).

2nd-

You have the books, you could've made it easier for others to find...book/chapter/line/pg/etc

3rd-

He never over sold the 7.Qa4 line. If he did anything, he clearly warned it being drawish, not being played much (except for a couple of White wins) and gave options to enter Tarrish if comfortable with it. Go back and read the beginning of the chapter (book 3 chptr 8 I believe...titled Open Lines).

4th-

IQP, not here...so why compare? You're probably better off with a middlegame book looking for how to play with/against it.

5th-

I can't imagine trying to write a repertoire book everyone will go over with fine toothed comb (even almost 10 years later and with engines). Also, you have to keep away from other authors' lines in the same series (they overlap).

6th-

Repertoire books do have their limits. Some writers publish them while still playing. They're not intended to be super GM repertoire books.

7th-

2.g3 never sat well with me anyway (not that I ever adopted the English for long)

8th- thanks for sharing what you've found, have a little mercy next time