This book is "must-have" reading for any aspiring slugger or student of the game of baseball. Be aware, however, that the book's value does not lie in the specifics of technical hitting instruction. This is much more hitting "theory" as relayed by Ted Williams from his years of experience. There is little, if any, practical detailed instruction on developing mechanics for swinging the bat. On one hand, the book is absolute gospel; I don't think anything in it could be seriously disputed, and to do so is to question the genius of a man whom baseball history shows to be one of the greatest hitters (and philosophers of hitting) that has ever lived. On the other hand, for Ted Williams to offer his personal philosophy and methods for hitting is similar to Tiger Woods trying to teach someone how he hits a golf ball. It might be great information for the rare few that can in some way duplicate Ted's or Tiger's physical abilities, but for a vast majority of players (especially very young players) who lack power, 20/10 eyesight, and one-in-a-million type hand/eye coordination, this book will (at best) offer little to improve their performance and (at worst) may actually lead to swing techniques that make the game more difficult.
For anyone who has spent any time studying the instruction of mechanics for the baseball swing, you already know that the methods of hitting fall into two primary camps. These methods can be differentiated by their beliefs on what is the "proper" swing plane (i.e., what path the bat takes in route to intercepting the pitched ball.) One side is often called "level swing" or "linear", where the swing is more level to the ground, and the other side (where Williams stands) promotes a swing level to the flight of the pitch (where the pitch is following a downward arc from the pitcher due to gravity and the elevation of the pitcher in relationship to the strike zone.) Therefore, the "level" swing that Williams promotes is, in practice, what is commonly known as an "upper-cut" at the ball. This method is commonly adhered to by those who teach "rotational" hitting (as opposed to "linear" hitting.)
Williams himself states several times throughout this book (although the statements are made in passing, and never really expounded upon) that his method for hitting would NOT be recommended for players that don't have the power to hit the ball out of the ballpark. This is where the problem really begins. How many baseball players aspire to be homerun hitters? ALL OF THEM! How many of them truly can be? Very few. An analyst on ESPN recently made the statement, "Just because some guy hits 20 homeruns in a season, people want to label that player a homerun hitter. Not so!" It is a very difficult thing (and quite counter-intuitive to an athlete's competitive nature) to identify and yield to the limitations of your athletic ability. However, Branch Rickey, one of the greatest talent evaluators and baseball minds in history, held the firm belief that it is impossible to teach a player to hit with power. You either have the skill from birth, or you don't. Ted Williams had it. Barry Bonds, Albert Pujols, ARod, Chase Utley, Josh Hamilton have it, just to name a few. This isn't just a matter of getting in the weight room and pumping iron. It pertains to the player's natural ability to generate fast, efficient motions of the body that will result in maximum kinetic energy. You are either born knowing how to generate optimal force or you are not. For those that are, then a technique similar to Ted Williams' is probably best for you.
Some of the biggest truths in the book are what make the book both universal and, at the same time, less useful for baseball instruction. Williams makes very general statements about proper mechanics, but then says that the 10 greatest hitters have 10 different styles. The times that he does make a concrete argument (like "upswing is the only way to go") it is placed under the caveat "if you have enough power to make it work." Which, as I have said, very few players truly possess.
Williams also covers his personal strategies for facing pitchers - how he takes more pitches in early at-bats and uses the data he collects for strategies later in the game (i.e., his third, fourth, and fifth at-bats in the game.) Well, if it's not obvious, this advice is nothing more than a fossil of a bygone era. In the modern age of the relief pitchers and situational substitutions, practicing this type of strategy is almost impossible. A professional hitter will be fortunate to get three at-bats against the same pitcher in one game. Hitters at the lower levels of amateur baseball usually play shorter games, and even if one does face a pitcher multiple times, the performance at that level usually lacks the kind of consistency needed to successfully make any sound assumptions.
To summarize this review, I think this book provides an excellent reference point for any student of the game of baseball. Translating the instruction in this book into improved success in the batter's box will require a more thorough understanding of the mechanics of hitting, and a disciplined, discerning athlete to cherry-pick the portions of this book that can actually be applied with his own ability level.