Undoubtedly, Brazilian Jiu Jitsu has proven itself to be indispensable in the ring of Mixed Martial Arts. Does this translate to the street?
I believe so, but not without Muay Thai (another style that's proven itself in the MMA's ring), and, IMHO Taijitsu and something of the nature of Pencak Silat.
This book has effective techniques for grappling situations. Royce has proven he is one of the best of the world in this area, again and again.
However, it falls a little flat with the grabs (This is where Taijitsu comes in better). The techniques shown in this book for grabs, are what would be shown as "introduction techniques". They introduce a concept (pulling at the thumb), but by themselves, won't work very well. BTW...In the MMA ring, no one will ever grab somebody by the wrist. Maybe that is why this area of the book proves skimpy
The strikes are fairly flat too. Royce has proven himself against striking arts repeatedly too, but his main concern is to get inside (The Gracie's all excel at getting inside). Then again, you only need to "master" a few strikes to be effective. However, Muay Thai and other arts, such as boxing will train you a lot better at this.
WARNING: The knive techniques in this book will likely get you cut up or killed. They are extremely clumsy, and will only work if your attacker moves like a robot, or if you get lucky. The only system I've seen with effective techniques against a knife, is Pencak Silat (or similar styles)
Two more quick notes:
One. Brazilian Jiu Jitsu, IMHO, is probably the most important style for a girl to learn in order to prevent being raped. Even an effective striker will often get overpowered by a larger, stronger, and tougher attacker. Also, in the case of date rape, a girl may already be in a clinch before she realizes something is going wrong. Bottom line, this style works well on larger, stronger attackers. (If you are well practiced)
Two. Can one learn from a book? Yes and No. Brazilian Jiu Jitsu: Yes, if you have a few good training partners who don't give you the move. You can go all out in practice and not get hurt if you are mindful and smart. It would help if you have some street fighting experience, or training in a similar art, BUT you would progress MUCH faster with a qualified instructor. You will certainly miss some key elements without an instructor, however, you may well get good enough to save your butt.
Striking arts: No. I don't think you could learn something like Muay Thai without a qualified instructor (Though a good book might help in your practice). Reason being, you can't tell if you are doing something effectively without knocking each other senseless, even with pads and gloves.