Expert Repertoire against Queen's Gambit Declined

It goes without saying that Queen's Gambit Declined is one of the most reliable weapons for Black. Even at the highest level, White is struggling to create problems. The fact that in his World Championship match against Carlsen, Caruana opted for this opening tells enough.
In his new database, GM Roiz deals with the difficult task to suggest a repertoire against Queen's Gambit Declined. In this extensive survey, Roiz comes up with a number of rare concepts and novelties in topical positions. At the very least, we can say that his suggested repertoire creates tons of practical problems for Black.
The database consists of 13 theoretical chapters and 15 interactive test positions.
The starting position of the current database arises after the moves 1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 Be7 5.Bf4 0-0 6.e3
At this point, Black has a variety of possibilities, the main line being 6...c5.
Now, we shall take a brief look at the different chapters.
Chapter 1 - 6...a6
A relatively rare move, though it was played by few strong GM's, such as Dubov and Ivan Sokolov. As usual, Black's main idea is to solve the problem of his light-squared bishop by means of ...b7-b5, followed by the fianchetto.
At this point, Roiz suggests 7.cxd5!?
Here is how the author justifies this choice:
There are a few other interesting possibilities at White's disposal, but I like this well-timed exchange. In the Carlsbad pawn structure, which arises after exd5, Black will struggle to find a good spot for his bishop.
The analysis of Roiz proves that White keeps a slight edge in all the lines.
Chapter 2 - 6...b6 7.Be2 Bb7
This is the most common choice. Black goes for the most natural way of development with ...c7-c5 to follow soon.
In this position, Roiz goes for straightforward 8.cxd5. The point is that with the Black's light-squared bishop already committed to b7, the structure arising after 8...exd5 is always favourable for White. In his analysis, the author demonstrates the right way of handling this type of positions.
The main move for Black is 8...Nxd5 when Black usually takes on d5 with a piece. Later on, Black usually tries to carry out the ...c7-c5 break. After reading the annotations to this chapter, you will see that in the arising symmetrical structures, White keeps a slight edge due to his active pieces and the weak c6-square.
Chapter 3 - 6...b6 7.Be2 Ba6
Compared to 7...Bb7, this is a more active continuation. In this case, however, White can enter a position with a pawn up where Black's compensation would be questionable. The main line goes 8.cxd5 Nxd5 9.Nxd5 Qxd5 10.Bxc7.
Taking the pawn is White's most principled approach. Further examinations prove that Black struggles to obtain sufficient compensation for the pawn.
Chapter 4 - 6...b6 7.Be2 dxc4 8.Bxc4 Bb7
This natural move is the top choice. The light-squared bishop is well placed now and makes it more difficult for White to expand in the centre with e3-e4.
After 9.0-0, besides the main move 9...a6, Roiz examines 9...c5, 9...Nbd7, and 9...Nh5. In all the lines, sooner or later, Black plays ...c7-c5 and after dxc5 we get the known symmetrical pawn structure. Roiz shows that it is not so easy for Black to equalize in all these positions.
Chapters 5 - 7 - 6...Nbd7 7.Be2 dxc4
In the next few chapters, GM Roiz is dealing with the flexible 6...Nbd7
This developing move gained some popularity in the late 2000s, and at some point, it was even more common than the ''classical'' 6...c5. Black is aiming to challenge White's centre on the next move when after dxc5 it is always possible to recapture with a knight.
Chapters 5-7 examine the position arising after the moves 7.Be2 dxc4 8.0-0.
This is the point of placing the bishop on e2. White can delay the recapture on c4.
In Chapter 5, Roiz covers the move 8...a6. Black is planning to expand on the queenside by playing ...b7-b5 followed by ...Bb7 and ...c7-c5. Therefore, White should settle for 9.a4!
When the black knight is already committed to d7, weakening the b4-square is not an issue for White. He is now ready to take the c4-pawn in comfort. Note that the moves 9...b6 and 9...c5 are now well met by 10.d5!
In Chapter 6, the author analyzes the straightforward 8...c5.
After 9.dxc5, Black can choice between 9...Bxc5 and 9...Nxc5. In both cases, White is playing for a win in a slightly better risk-free position.
Chapter 7 features mainly 8...Nb6
A double-edged move. The c4-pawn is covered now, but Black's control over the centre has diminished. The most principled reaction seems to be 9.Qc2! The most flexible choice. White connects his rooks and makes the thematic e3-e4 advance work soon.
Additionally, in this chapter, Roiz explains the structure arising after 8...Nd5 9.Bxc4 Nxf4 10.exf4. He shows why White always keeps an edge in such positions.
Chapter 8 - 6...Nbd7 7.Be2 c6
A solid continuation. Black delays the development of his light-squared bishop but strengthens d5 so that now Nf6-h5 is a considerable option.
After 8.0-0, Roiz examines several continuations - 8...dxc4, 8...b6, 8...a6, and 8...Nh5. Since the first three moves are slightly passive, Black should probably go for 8...Nh5. In this case, however, White can simply connect the rooks with 9.Qc2. As we have already mentioned the structure arising after 9...Nxf4 10.exf4 can be quite tricky for Black.
The main position of the remaining part of the database arises after 1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 Be7 5.Bf4 0-0 6.e3 c5 7.dxc5