If you are fascinated by the extreme measures that have characterized the "cults" that the media has highlighted for us, this book is a great corrective. It provides details about the events surrounding the violence you saw/heard on screen--for Jonestown, Waco, Aum Shinrikyo, Solar Temple and Heaven's Gate.
What could we have missed? For example, and this is a major premise of the book, the fact that the anti-cult coalitions, government agencies, and media played a huge role in the intensification of events leading to the climaxes of violence. In other words, all factors involved in "cult" violence are not only internal factors (eg. psychotic leaders brainwashing victims into compliance). Conflict is exacerbated, accelerated and even initiated often from the outside.
Whether this book "overcorrects" is debatable. But it certainly adds to understanding the complexities involved in new religious movements that go up in smoke.