The reason this book is good may not so much be content, but the fact that there are no other books on the French Defence designed for beginners. I know somewhere there is a Learn French with the Read and Play Method...
There are a lot of good reasons to play the french. First, it's an opening that gets a lot of play in top level tournaments, so you always have something new going on in your opening. Second, it is a counterattacking opening, just like the sicilian. The real difference is that in the french you don't have to learn as many structures to play, unless you want to.
I can't really comment on the section about the Winawer, as I have no desire to play it. However, the section on the classical, Tarrasch, and Advance have helped me understand the "why" behind the varations I've memorized. Just reading through this, I have realized points when in games I had a winning position because of an opponents tactical or positional blunder, only to lose it.
The games in the book are mostly master level games from the last couple of years, giving the book an up to date feeling. Plus, all lines of the french are covered. The entire book won't be helpful to everyone though, unless you're looking to find lines that suit you. All in all, get this book, play through the games, and you'll have a great base to expand on for the future.