Simple Chess by GM Michael Stean is one of the best chess books I've come across in 25+ years as a chess player.I'm just a ordinary club standard player but I'd say that this book would be useful for players upto ELO 2000.
It is divided into seven chapters: Introduction, Outposts, Weak Pawns, Open Files, Half-open Files minority attack, Black squares and white Squares, Space.
As GM Stean says in the intro this book is not for beginners, you need to understand all the basics first (like forks, pins, double and discovered check, skewers, mates with queen and rook etc., and basic opening ideas). so if you have gone through the basics, played some games and began to understand how the pieces work together, then Simple Chess is for you. An important note, though, is this is a book on middle game strategy and does not show any tactical elements of the game.
Stean shows how, sometimes small, positional advantages may be enough for victory. He uses top level games (upto the 1970's when this book first came out) and he very carefully and clearly annotates them.
One disappointment with this new algebraic edition is many textual errors have crept in (to correct these see the reviews on Amazon.com USA).
If you think you need a easier general chess book first then try 'Better Chess for the Average Player' by Tim Harding.
When you've gone through Simple Chess and if you like it then good choices would be, Ludek pachman 'Modern Chess Strategy' and 'My System' by Nimzowitsch.