Krakauer’s a compelling writer, and he’s turned his talents to something harder to write about than his last two books (which were also great).
The Mormons intrigue me, mostly because they are heterodox Christians. I.e., they do not believe in the orthodox doctrines of the faith that one would generally subscribe to in order to be called “Christian.” They’re essentially theological gnostics, and Gnosticism was declard heretical in Christianity in the fourth century. Also, Mormon social structure fascinates me. They’re wonderfully anti-individualist and communitarian in a very particular way. And I’ve just been plain interested in the Mormons since doing a lot of research on them for a professor in college.

I’m sure the LDS hierarchy was none too happy about the book, but it seems fairly even handed to me. Krakauer’s generally pretty good about being fair to his subjects and trying to enter their worldview, even if he doesn’t “approve” of it.