I've followed Atran's scientific studies on the cognitive foundations of religion over the last few years as well as his New York Times opeds on the kinds of people and events that keep Al Qaeda and its associates going. Although there are glimmers of how the two lines of research coalesce in these previous accounts, they give no hint of the richness of the connections explored in this book.
Where before there was "only" a general description of the the psychological structure and evolutionary underpinnings of all religions, now we have also an historical account of how history and circumstance molded these universals into the particular religions we know today, including their relation to the history of war and violence, as well as the development of modern civil and human rights.
Within this context, terrorism and violent extremism, including suicide bombings and genocide, are not so much bizarre exceptions to human behavior as infrequent but recurrent phenomena that punctuate and shape a course of human history that, while contingent and not foreseeable in advance, now looks as coherent and inevitable "as a gathering storm in a video run backwards."
But the most politically important and intellectually intriguing aspect of the book is the way the author weaves these initially disparate lines of thought into a practical program to end wars, including the so-called war on terror, by reframing each side's sacred values (such values, unlike material values, cannot be bargained with or compromised in a "business-like" negotiation sense and so must be managed in other ways). This is in order to accomplish what Abraham Lincoln advised as the best way to win wars when he said to an irate Union sympathizer who berated him for trying to treat his enemies as people essentially no different from others: "Why madam, do I not destroy my enemies when I make them my friends." Of course, notes Atran, this is not how you deal with Al Qaeda, but how you try to treat the the kids who are caught along with the driftwood in the riptides of globalization between "Yes we can" and "Happiness is martyrdom."
There are other aspects of the book that have been well reviewed elsewhere, including veteran war reporter Jason's Burke's assessment (in The Guardian and The Observer) of how Atran tracked down the social networks involved in the 9/11, Bali, and Madrid train bombings; and the New Scientist's take on how Talking to the Enemy debunks some of the most virulent and unsubstantiated claims against religion and its relation to terrorism proffered by the "new atheism" of Sam Harris, Richard Dawkins, and others.