Middlegame books

I need some suggestions on good middlegame books. I'm already familiar with the basic ones like Silman, Simple Chess, Think like  aGM etc.

The Yusupov series

Small Steps to Giant Improvement, Sam Shankland (on pawn play)

Good game collections of which there are many

I agree with @madratter7 on the Yusupov books. In addition:

For calculation and thought processes: Soltis, The Inner Game of Chess (much better than Think Like a Grandmaster); Soltis, How to Choose a Chess Move; Benjamin, Better Thinking, Better Chess.

For strategy and positional play: Pachman, Complete Chess Strategy (3 volumes; also published in an abridged version called Modern Chess Strategy); Marović, Understanding Pawn Play in Chess; Marović, Dynamic Pawn Play in Chess; Soltis, Pawn Structure Chess; Flores, Chess Structures: A Grandmaster Guide. I haven't seen Shankland's book yet but have heard good things about it.

Game collections: Bronstein, Zurich 1953; Reshevsky, Reshevsky's Best Games of Chess; Réti, Masters of the Chessboard.

As I understand it, the official order is Build-1, Boost-1, Evolution-1, Exam-1, Build-2, Boost-2, etc.
http://www.qualitychess.co.uk/ebooks/Build-up-Your-Chess-1-exceprt.pdf
https://web.archive.org/web/20140708103321/http://www.chesscafe.com/text/review699.pdf
http://www.qualitychess.co.uk/ebooks/Build-up-your-chess-2-excerpt.pdf
http://www.qualitychess.co.uk/ebooks/Build-up-Your-Chess-3-exceprt.pdf
https://web.archive.org/web/20140708103659/http://www.chesscafe.com/text/review778.pdf
http://dev.jeremysilman.com/shop/pc/Boost-Your-Chess-1-77p3744.htm
http://www.qualitychess.co.uk/ebooks/Boost-Your-Chess-1-excerpt.pdf
http://dev.jeremysilman.com/shop/pc/Boost-Your-Chess-2-77p3745.htm
http://www.qualitychess.co.uk/ebooks/BoostYourChess2-excerpt.pdf
http://dev.jeremysilman.com/shop/pc/Boost-Your-Chess-3-77p3746.htm
http://www.qualitychess.co.uk/ebooks/BoostYourChess3.pdf
https://web.archive.org/web/20140708103149/http://www.chesscafe.com/text/review834.pdf
http://www.qualitychess.co.uk/ebooks/Chess-Evolution-1-excerpt.pdf
https://web.archive.org/web/20140708085817/http://www.chesscafe.com/text/review843.pdf
http://dev.jeremysilman.com/shop/pc/Chess-Evolution-2-77p3643.htm
http://www.qualitychess.co.uk/ebooks/Chess_Evolution_2-excerpt.pdf
http://dev.jeremysilman.com/shop/pc/Chess-Evolution-3-Mastery-77p3753.htm
http://www.qualitychess.co.uk/ebooks/Chess_Evolution_3-excerpt.pdf
http://www.qualitychess.co.uk/ebooks/QandAwithArturYusupovQualityChessAugust2013.pdf
https://www.qualitychess.co.uk/ebooks/Revision&Exam1-excerpt.pdf
"Fundamentals first, then Beyond the Basics and finally Mastery. Follow the colours!" - Yusupov

https://chessbookreviews.wordpress.com/tag/sam-shankland/

https://www.newinchess.com/media/wysiwyg/product_pdf/7804.pdf

http://www.jeremysilman.com/shop/pc/Inner-Game-of-Chess-The-77p3897.htm

https://web.archive.org/web/20140708094114/http://www.chesscafe.com/text/review545.pdf

https://www.newinchess.com/media/wysiwyg/product_pdf/9071.pdf

http://store.doverpublications.com/0486202909.html

https://web.archive.org/web/20140708110136/http://www.chesscafe.com/text/review249.pdf

http://www.gambitbooks.com/pdfs/Understanding_Pawn_Play_in_Chess.pdf

http://www.gambitbooks.com/pdfs/Dynamic_Pawn_Play_in_Chess.pdf

http://theweekinchess.com/john-watson-reviews/books-of-many-flavours

https://web.archive.org/web/20140708101523/http://www.chesscafe.com/text/review908.pdf

https://chessbookreviews.wordpress.com/tag/chess-structures-a-grandmaster-guide/

https://www.newinchess.com/media/wysiwyg/product_pdf/7495.pdf

http://exeterchessclub.org.uk/content/review-zurich-1953-bronstein
http://theweekinchess.com/john-watson-reviews/john-watson-book-review-106-zurich-1953-by-najdorf
http://store.doverpublications.com/0486238008.html

http://www.thechessmind.net/blog/2012/4/1/book-notice-richard-retis-masters-of-the-chessboard.html

https://www.newinchess.com/media/wysiwyg/product_pdf/9017.pdf

Try Small Steps to Giant Improvement by GM Sam Shankland 

Judgement and Planning in Chess by Euwe. Very under rated IMO is a good one.

The Art of Attack by Vukovic which compliments the above

https://web.archive.org/web/20140708234424/http://www.chesscafe.com/text/aac.pdf