This book is part of a three-volume endgame mastery course by John Nunn, a grandmaster with many previous innovative endgame books to his credit. The first volume, Understanding Chess Endgames, was originally meant to be an introductory chapter to the book Nunn wanted to write, but his "introductory" material was voluminous to justify an entire book to itself. That volume is a pretty good endgame course in itself, almost as good as Howell's excellent but prohibitively expensive Essential Chess Endings: The Tournament Player's Guide.
This book goes further in depth into all endgames that do not have a Rook on the board. The material is simply outstanding. Nunn's intent is not to offer an academically-correct introduction to the endgame, but rather to prepare the student for the rigors of over-the-board play. To that end, this volume (and volume 2, which focuses on endgames with a Rook) focuses on three principles, which Nunn believes must be blended seamlessly at all times to play the endgame well. The first, knowledge, comes from the first book, mentioned above; it involves having the right sort of ideas in mind before sitting down at the board. The second, imagination, stems in part from talent and in part from experience. The third, calculation, shows up as vital in every example in this book. It's the need to blend these factors -- ALL the ideas, ALL the imagination, and especially, ALWAYS careful calculation -- which Nunn highlights so well. His examples show time and time again how strong players miss important nuances, not only during play but even later when annotating games, and thereby lose half-points and even full points after hours of struggle. The only preventative measure, in Nunn's opinion, is to develop the habit of playing on general principles while at the very same time engaging in accurate calculation at every step. This book provides hundreds of examples on just how to do this -- and the price to be paid for insufficient attention to detail.
I don't want to scare off potential readers. The material is not skull-crackingly complex. Endgames don't have subtle maneuvers and incomprehensible issues such as piece coordination. Endgame play, above all, is clear. Nevertheless, Nunn really succeeds in driving hom his point: in addition to having the right principles in mind, and combining them in imaginative ways, the player must also calculate with care, or winning or drawing nuances will be easy to overlook. As a result, each of the examples needs to be studied with some care and the lessons thoroughly absorbed. This is not a book to read in a day or even a week, but in a month or two. It is accessible to any tournament player, yet demands effort and attention, which it will richly reward.
For years, Nunn has been among those trying to counter the "conventional wisdom" in chess, which describes middlegames as the provice of tactics, and endgames as the province of prior knowledge. To the contrary, he shows the endgame as the most tactical phase of them all. And to good end: as others, such as Beliavsky, have demonstrated in their books, strong players fail in the endgame over and over, not because they lack knowledge or are insufficiently imaginative, but because they fail to consider tactical features of the position.
Anyone who studies this book and its two companion volumes will have very little to fear from anyone up to Grandmaster strength in the endgame. Tremendous achievement to John Nunn, and thanks for such a great training program.