... In "Comprehensive endgame course" , Averbakh mentions that endgame study must precede any other study. Comprehensive endgame course waswritten with collboration of some of the best Soviet theoreticians and teachers and it was supposed to bea series of books that would be an endgame refference for every level. ...
This is what I found:
"... As a whole, Comprehensive Chess Endings will be a basic reference work on the theory and practice of the endgame, indispensible for the analysis of adjourned positions and for correspondence play. It will also be useful as a text-book for rated players wishing to raise their standard of endgame play."
And, in the beginning of Averbakh's Chess Endings Essential Knowledge, I also found:
"... the study of the simplest endings should precede the analysis of the openings and the middlegame."
"I conceived the idea of writing a popular booklet devoted to the endgame back in the early 1950s, when I was working on an encyclopaedic reference work intended for players of high standard. Out of the mass of information on the endgame, I thought it was important to select the minimum which any chess enthusiast should know in order to handle competently the concluding phase of the game. It turned out that it was not necessary to know such a great deal."
... and a copy of Fundamental Chess Openings. ...
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"... [Fundamental Chess Openings] is not particularly suited for players who are just starting out. I would imagine players rated at least 1400-1500 would get the most benefit from this volume. ..." - FM Carsten Hansen (2010)
https://web.archive.org/web/20140626173432/http://www.chesscafe.com/text/hansen128.pdf
http://www.jeremysilman.com/shop/pc/FCO-Fundamental-Chess-Openings-76p3561.htm
One can get an idea about what it is like to try to read this sort of book by looking at this sample:
http://www.gambitbooks.com/pdfs/FCO_Fundamental_Chess_Openings.pdf
Winning Chess Openings is not as coprehensive as FCO, but probably a lot more readable. If I remember correctly, it was written around 1999. Here is a review:
https://web.archive.org/web/20140627132508/http://www.chesscafe.com/text/hansen173.pdf
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"... For inexperienced players, I think the model that bases opening discussions on more or less complete games that are fully annotated, though with a main focus on the opening and early middlegame, is the ideal. ..." - FM Carsten Hansen (2010)
"... Everyman Chess has started a new series aimed at those who want to understand the basics of an opening, i.e., the not-yet-so-strong players. ... I imagine [there] will be a long series based on the premise of bringing the basic ideas of an opening to the reader through plenty of introductory text, game annotations, hints, plans and much more. ..." - FM Carsten Hansen (2002)
https://web.archive.org/web/20140627055734/http://www.chesscafe.com/text/hansen38.pdf