The book itself is mostly solid, with clear glossy photographs, a decent layout, and lots of drills. But it also has a couple problems.
The good:
The drills layout is logical. Follow the arrow and you get a series of pictures as the instructor moves through the drill. There's a text also describing what the instructor is doing. By comparing the two, it's easy to get a solid feel for each drill.
The book is divided into 12 months, with each month containing 4 weeks, and each week containing five days. Each day usually has 1 or 2 drills. Some will seem familiar to anyone who has been to a bjj class recently. I'm sure if you follow the drills in addition to your current training you will end up a better player.
The first few months focus on strength, conditioning and balance, the next few on basic movements, and then more advanced drills are introduced. It's a relatively logical sequence, with later drills building on earlier drills. Most everyone who makes it to a class will be familiar with a good portion of the drills in the first four months. Some heavier trainees might strain a bit on some drills, but that's why they need to do them. Comparatively, some lighter trainees might find some of the drills too easy. Overall, solid.
The bad:
The initial month has no drills, just a couple pages noting that diet is important and that you should work on that for a month. While diet might be important, it would have been better to mention that as part of the introduction or the first several chapters, and not cut into drill time. The final month is also under 2 pages, just noting that the trainee should review and work on weak spots. 10 months to better brazilian jiu jutsu.
10 months of drills could still be pretty solid. However, a good number of the drills assume you have a swiss ball, and a few also assume you have a balance board or two. A mat is also assumed, but that assumption is completely understandable. Even these are acquirable without too much trouble.
My big issue comes with the lack of solo drills in the book. Most of the drills in chapters two and three can be done and are shown solo. Very, very few other drills in the book are solo drills. You might be able to attempt some of the drills alone where the partner is least involved, but it's a dodgy prospect at best.
For someone like me who picked up the book to work on my own time with no practice partners accessible, this is crushing. The only time I have partners accessible is usually during class hours, and those are better spent with a live instructor. So, for me, 2 months to better brazilian jiu jutsu. And most of those drills I knew already.
Overall, if you have a training partner, the necessary gear, and the time and the will to implement the program, four stars. Without the training partner, two stars.