Samuel Reshevsky is the ideal person to write a book on positional play because that was exactly the way he played: positionally. Reshevsky preferred to crush his opponents slowly, like a python, rather than to win with a blaze of tactics. Reshevsky was capable of great tactics, but felt it easier and more secure just to win by the slow build-up, gaining small advantages and then waiting for the opponent to throw himself on the sword with a brash counter-attack.The disadvantage is this takes a long time and most of the games in this book are long, but that makes them more instructive. A game won by sharp tactics does not teach much, unless that exact tactic arises again. The slow build-up that Reshevsky specialized in can be repeated again and again to bring home the point every time.Reshevsky goes through positional values, such as open files, avoidance of doubled pawns, consequences of weak pawns, bad bishops, unsupported pawn chains, blockade vs. breakthrough, using minority attacks, passed pawns in the middle game and rooks behind passed pawns.In each of these cases, he uses a top level grandmaster game to illustrate it, showing how the greatest players use these motifs to win their games at the highest levels.
I didn't finish more than 10% of this book. Following the games was painfully slow, and that's without having to deal with the many typos that someone had corrected in pencil in my library copy. The openings are not common today, and the games too good to be relevant to me.
45 years have passed since this book was originally published, so any remarks about openings should be viewed with a healthy dose of skepticism. Since this edition, computer analysis has become much more popular so it's probable that some of the variations cited by Mr. Reshevsky would not hold up under such scrutiny.
A major problem with the book, however, is the number of mistakes in the transliteration from descriptive notation to algebraic notation.
Still holding up well, however, are Reshevsky's comments on positional elements of chess; in this context, he is in his element.
All in all, though, there are probably better books on positional chess available that have been written since the turn of the 21st century.