Very easy question.
Obviously "My system " by Aron Nimzowitsch.
This book simply classical and covers it all. This book is foundation and books like Fisher 60 games and teaches chess all came on top of this foundation and Fisher himself had to read and understand that foundation himself first and only THEN write his own ideas .
So it's been number 1 book and till today it's number 1 . I'm Russian trust me on this .
One can get some idea of the lasting scope of the respect for My System by looking at:
https://www.chess.com/article/view/the-best-chess-books-ever
Still, it might be noted that My System apparently did not occur to GM Yasser Seirawan as something to include in his list of personal favorites, and Aaron Nimzowitsch was not identified by the GM as a very worthy author.
Also, My System has accumulated some direct negative commentary over the years.
"... I found [the books of Aaron Nimzowitsch to be] very difficult to read or understand. ... [Nimzowitsch: A Reappraisal by Raymond Keene explains his] thinking and influence on the modern game in a far more lucid and accessible way. ... The books that are most highly thought of are not necessarily the most useful. Go with those that you find to be readable; ..." - GM Nigel Davies (2010)
In 2016, IM pfren wrote:
"My System is an iconoclastic book. A lot of things in there is sheer provocation, and it does need an expereienced player to know what exactly must be taken at its face value.
I love 'My System', and I have read it cover to cover one dozen times, but suggesting it to a class player is an entirely different matter."
"[Some things] ARE wrong, and it's not easy for a non-advanced player to discover those wrong claims.
Nigel Short has claimed that 'My System' should be banned. Stratos Grivas says that the book is very bad. I don't share their opinion, but I am pretty sure that there are more useful reads for class players out there."
Although he is a fan of My System, IM John Watson similarly acknowledged (2013) that:
"... Not everything in it has stood the test of time, ..."
http://theweekinchess.com/john-watson-reviews/john-watson-book-review-108-of-eplus-books-part-2-nimzowitsch-classics
One last point to keep in mind is that, even if My System would eventually help a player, it might not necessarily be helpful to a player now.
"... Just because a book contains lots of information that you don’t know, it doesn’t necessarily mean that it will be extremely helpful in making you better at this point in your chess development. ..." - Dan Heisman (2001)
https://web.archive.org/web/20140626180930/http://www.chesscafe.com/text/heisman06.pdf
A My System sample can be seen at:
https://www.qualitychess.co.uk/ebooks/MySystem-excerpt.pdf
In #54, granfalloon recommenfds "Chess is my Life by Andor Lilienthal" -- I can't find record of such a book (though there is the Korchnoi book of the same title, of course). Anyone have or know more about this?
Not much. Mark Crowther (of The Week in Chess) stated that Andre published a biography (sic) in 1985 titled "My Life, Chess". A poster on Chessgames.com stated that he has Andre's autobiography in Hungarian, which to me implies that it hasn't been translated to English yet.
http://theweekinchess.com/chessnews/obituaries/andor-arnoldovich-lilienthal-1911-2010