Cults. Is there a topic more juicy? Who doesn't want to adapt a completely regimented lifestyle to help them avoid all the crap they don't want to do? But cults are not just religions, of course not. Cults can be gyms, MLMs, and support groups.
And this book goes into some depth about the language many of these groups adapt to divide themselves from anyone who's not in the cult. It's all pretty interesting, but it's not as juicy as a tell-all from someone who sold their soul, castrated themselves, or went into human trafficing. So don't expect that here.