As a student of the martial arts (Okinawan Kenpo Karate), we spend time studying self-defense. This is true of many martial arts systems, but is what you are training for realistic?
Rory Miller doesn't consider himself a self-defense instructor but rather a "violence" instructor. He wants to teach people about violence and how to prepare and deal with violence. Miller starts off outlining some of the issues with traditional training around self-defense. This could be from the techniques taught, how the attack is taking place, and how we are practicing these techniques. Do you pull your attacks? Miss on purpose so as not to hurt your team mate? Miller points out that these can lead to real issues on the streets that you better be aware.
From here Miller offers his own set of drills. They start off from a simple one-step training drill, to how to setup and how full-blown scenarios to mimic real world situations. Since this is a training environment Miller offers safety and coaching tips. Not all of the drills are physical, there are mental drills to run through too. Martial artists tend to focus on the physical aspects of self-defense without consideration to mental aspects (ditto for the legal aspects which Miller also talks about). Some of the drills are what can be described as "different", but in a good way as they make you think in a different way. This even goes for some of the physical drills. I won't go into these drills so as not to spoil it for future readers, but people should find then useful. Miller's afterwords ("Real Superpowers you can have today") would be great reading for anyone, those interested in self-defense or not.
What you won't find here are magical techniques. Miller isn't attempting to replace your training but rather add another element to your training. Very similar to how Tony Blauer states that his SPEAR system is a bridge to your self-defense toolbox.
If you train people in self-defense techniques, or interested in improving your own training in this area then I highly recommend this book.