Anyone who has ever read a chess book is probably familiar with the four key elements of position - force, time, space and pawn structure. This book contains the best treatment of the element of space that I have ever encountered.
Seirawan addresses the needs and treatment of each piece as well as strategic pawn play. His observations regarding the use of pawns to support N outposts are particularly insightful.
There is a very good treatment of B vs N and how to play this matchup from both sides. Creation and exploitation of weaknesses is explored in depth with an emphasis on focus that is rarely expressed in chess books.
Seirawan repeatedly stresses key themes such as utilizing all your pieces, or consolidating your position after winning material. These reminders are interwoven with the chapter material in a very natural and instructive manner. Example games or game fragments tend to illustrate several elements concurrently. The game commentary is very rich and instructive, and focused on the strategic principles, so there is little in the way of dense tactical variations.
This book is written in a very readable, engaging style. Seirawan is an excellent author as well as a top flight chess player. This book is probably best suited to club and tournament players advancing through USCF 1400 and higher.