It's a book about security. It's a book about how to think your way through security problems. Not just thinking about where to throw up barriers—also about how to think up policies that won't just backfire. It's all very well to say, "We should ban my upstairs neighbors from clomping around." But then when you try to think of what the consequences of clomping should be, how to give the police power to enforce the policy (should I let the police officers into my apartment so that they can measure whether my neighbors are too loud?), and whether that's really something that should ever by a priority for the police to enforce... Uhm, yeah, that rule doesn't sound like such a great idea anymore. This all sounds pretty straightforward, but we get this wrong all the time. Maybe you've studied game theory for years, but our skittery brains tend to throw all that out the window when we think the bad guys are coming up on us. So it's a good thing that this book talks about how to think your way through these problems. It might be a better book if it came with a big "DON'T PANIC" on the cover, but I guess that can wait for the next edition.