Often after a significant event or incident, journalists rush a book into print to capitalize on public interest about it.  It's very rare that one is as well written and fast-moving as this one.  Usually the writer tries to make it more than it is, perhaps not wanting to simply recapitulate reporting on the subject, but not really having the skills to provide needed context.  Kaplan and Marshall forego almost all of this in favor of a story that, while tragic, is tense and quick-moving.  In fact, only at the end, when they start to speculate that apocalypse cults will be the biggest threat of the 21st century, does the book start to feel loose and meandering.  

What's wilder is there actually is enough information in this book for an entirely different conclusion: that even a police force with the free hand that Japan's police provably have, in a nation where there are few rights once the police put their eyes on you, they can't actually handle organized terror any more than a free society could.  This conclusion is not explored.  Perhaps it was unimaginable to American reporters pre-9/11?  

If you've heard of Aum, or perhaps the sarin attacks, but don't know exactly what it was all about or how it happened, or the facts of the pursuit, this is a great place to start. It comes together as a great work of narrative journalism.