The first part is a collection of interviews bringing to life what happened in the Sarin Gas Attacks in Tokyo. You get a sense of the confusion as well as the moral dilemma faced by ordinary citizens and how emergency services were woefully unprepared for such an event.
The last half was written later due to criticism received by the initial publication. Here you have interviews of various members of Aum, the cult responsible for the attacks. Aside from the brief description, I couldn't muster up the will to read their stories.
This was a good read and helped give a sense of what went on before, during and the aftermath. It is real human stories.