I have mixed feelings about this book; on the one hand it's a wealth of great information, on the other it has quite a bit of pseudoscience in it, can be one sided, and can be condescending.
Let's give examples.
In terms of good things, there is an encyclopedic listing of everything you could want to know about BBQ, and a number of recipes. If you want to learn how to smoke using propane, charcoal, wood, or electric, the knowledge on how to get started is there. Meathead Goldwyn will walk you through the entire process, and if you absorb even a tenth of the material, you'll make some pretty good BBQ.
Where the book really falls short is the author (Meathead), enlists the help of a Physics professor to "bust myths" around cooking. The pair will present a "myth," and then explain why they can "bust" it.
However, the "busting" is not really robust science. For instance, the author shows an experiment where the Professor soaks meat in food coloring for 24 hours. As the food coloring stops penetrating further into the meat after an hour, the professor "busts" the myth that marinade times for more than an hour are necessary. Correlation is not, however, causation. The professors hypothesis is indicative of the ability of meat to absorb food coloring, not absorb flavor from a marinade. A real scientific test would have multiple tests over a wider range of factors. As a BBQ aficionado, I can tell you flavor definitely improves if you marinade for a long time (and some regional cuisines like sauerbraten take this to an extreme and marinade for days at a time). I cannot speak to the science of it, but it clearly has an effect, and many professional chefs would disagree with his "theories."
So, if you do read this book, you'll get good info, but take everything he says with a grain of salt.
Further, sometimes this cardinal sin of trying to make BBQ "scientific" ends up coming across as very condescending. The author went to Dreamland, a famous BBQ place in Alabama, determined to "bust" their cooking methods (as it goes against everything he believes is correct), and in the end had some very good ribs. He does acknowledge this, but should go a step further and indicate that actually he is a proponent of a specific style, but there is no reason one has to follow his hard and fast rules.
Another great example of this is his insistence that you practice many times keeping your grill the appropriate temperature over a long period of cooking time, without any meat on it. While it might make sense for people who are interested in competition BBQ to train, this seemed particularly idiotic to me. First off, fuel is expensive. Second off, adding meat to a grill changes the heat profile of the grill, so you might as well learn on actual meat. Just pick a forgiving meat like chicken thighs for your first time. You may make mistakes, but they'll be tasty mistakes! And although you might endeavor to cook at 225 F, if you clock in an average temp of 250 or 200 (as I did my first couple of tries with the smoker) the food will still come out good -- it'll just take more or less time to cook.
So, all in all, consider adding this book to your shelf, but beware, it's got some glaring issues.