From the back cover:
In Under the Banner of Heaven, John Krakauer shift his focus from extremes of physical adventure to extremes of religious belief within our own borders. At the core of his book is an appalling double murder committed by a pair of brothers, Ron and Dan Lafferty, who insist they were commanded to kill by God.

Beginning with a meticulously researched account of this “divinely inspired” crime, Krakauer constructs a multi-layered, bone-chilling narrative of polygamy, savage violence, and unyielding faith. Weaving the story of the Lafferty brothers and their fanatical brethren with a clear-eyed look at Mormonism’s violent past, Krakauer examines the underbelly of the United States’ most successful homegrown faith, and finds a distinctly American brand of religious extremism.

Review:
I hadn’t realized I was going to get so much information about Mormonism in this book, and I now know more than I ever wanted to about it. Most of the included history was contextually important for understanding the background of the Lafferty brothers (who were actually the focus only about 1/4 of the time), but sometimes it wore on interminably.

Krakauer’s writing was clear and easy to understand and fulfilled the promise of remaining “clear-eyed.” The portrait of Mormonism that was presented may’ve been unflattering, but it wasn’t malicious. Events were recounted and allowed to stand on their own without being made to serve one opinion or another.

I particularly found interesting the hearing to determine whether Ron Lafferty could be deemed delusional (and thusly incompetent to stand trial) because of his extreme religious beliefs, or whether that would mean that everyone who believes in irrational things (an example given was transubstantiation) as part of their religion must also be considered insane.

All in all, Under the Banner of Heaven was informative and accessible. I learned a great deal and was prompted to ponder a great deal. That said, as I neared the end I was really ready for it to be over.