user21110: After following the studying advises of a Chess Stack Exchange fellow (PhishMaster, if you read this, thank you!) I'm about to break 2200 Lichess elo finally. I think it is time to truly and deeply study the openings and defenses I enjoy playing. That is why I'm looking for in-depth books on the QG (or specifically QGD) and French Defense.
I'm not looking for introductory books, or key-ideas-presentations sort of literature; I'm aiming at studying and memorizing lines and variations in depth, for I feel I have come to the point this is necessary to improve my game.
An excellent example of the type of book I want is Pachamn's Queen's Gambit Declined, but the problem is the book is clearly outdated and I know many of the lines it presents as solid have been refuted both by the human mind or by the engines (still excellent book, don't get me wrong). 
What books of this sort can you recommend me on this openings?

user23148: I am 2300 USCF and I recommend Boris Avrukh's books. His main focus has been the Catalan for some years now but the QGD is well covered.

user18738: Sadler QGD book is fantastic - I know some pretty strong players who don't even play QGD as black (or 1.d4!) who read that book just for the instructive value. Don't use the lines themselves (very old book) as a repertoire if you are >2200 FIDE (lichess I don't know how to translate but it is probably lower than FIDE) but QGD is more about understanding - get it!
One of best chess books I ever read and I used the understanding I got from this book to make my own QGD repertoire and draw with GMs in tournaments. I stopped using QGD so much when I got a bit higher rated and face a lot of lower rated players - winning as black can be a bit of a slog in the duller lines.

21110: <p>After following the studying advises of a Chess Stack Exchange fellow (PhishMaster, if you read this, thank you!) I'm about to break 2200 Lichess elo finally. I think it is time to truly and deeply study the openings and defenses I enjoy playing. That is why I'm looking for in-depth books on the QG (or specifically QGD) and French Defense.</p>

<p>I'm not looking for introductory books, or key-ideas-presentations sort of literature; I'm aiming at studying and memorizing lines and variations in depth, for I feel I have come to the point this is necessary to improve my game.</p>

<p>An excellent example of the type of book I want is Pachamn's <em>Queen's Gambit Declined</em>, but the problem is the book is clearly outdated and I know many of the lines it presents as solid have been refuted both by the human mind or by the engines (still excellent book, don't get me wrong). </p>

<p>What books of this sort can you recommend me on this openings?</p>
 23148: <p>I am 2300 USCF and I recommend Boris Avrukh's books. His main focus has been the Catalan for some years now but the QGD is well covered.</p>
 18738: <p>Sadler QGD book is fantastic - I know some pretty strong players who don't even play QGD as black (or 1.d4!) who read that book just for the instructive value. Don't use the lines themselves (very old book) as a repertoire if you are >2200 FIDE (lichess I don't know how to translate but it is probably lower than FIDE) but QGD is more about understanding - get it!</p>

<p>One of best chess books I ever read and I used the understanding I got from this book to make my own QGD repertoire and draw with GMs in tournaments. I stopped using QGD so much when I got a bit higher rated and face a lot of lower rated players - winning as black can be a bit of a slog in the duller lines.</p>
