Under the Banner of Heaven by Jon Krakauer.  Just finished this book.  Very interesting book.  It starts out with Elizabeth Smart and the relationship between her abductor and the Mormon religion.  He uses this to introduce extremist thinking within the Latter Day Saints theology. 

I started the book with the impression that it would be about life within a Mormon community, but it's clear that he doesn't deal with that at all.  He talks about it, but his focus is on how extremist sects deal with and clash with the rest of the United States.  He talks a lot about the history behind the faith, and also uses the exploits of the Lafferty brothers to illustrate some of the consequences of the influences that history has on the philosophy of people on the fringe of this belief system. 

I found the discussion of the trial of one of the Lafferty brothers to be very interesting.  Basically, Dan Lafferty killed his brother Alan's wife and child following divine instruction.  To this day Dan proclaims his innocence because the act was a command from god.  He admits to killing them, but says he's innocent because he was just an instrument to god's will.  This has raised serious questions concerning his mental stability and how it should affect his arraignment and sentencing.  It has gone to the Supreme Court, but they refused to hear the case. 

It's a paradox, of sorts.  Some want to defend Dan with insanity.  He insists he is sane, and there are doctors that have made statements in court for both sides of the issue.  The logic is this, if I can get it right.  He must be insane because he killed another human being and feels no remorse, says he's innocent while admitting to the act.  He's hearing things, because 'god told him to kill them'.  This alone proves, to some, that he's insane, because what sane person hears things like this.  That sounds fine, except that it's true of 'normal' people as well.  There are lots of religious people that claim to 'talk to god'.  Can they be labeled insane as well?  If so, where does that lead?  If not, then nobody can label Dan insane either, and it becomes perfectly plausible that 'god told him' to act in such a way.  If this is allowed, what's to stop others from killing and proclaiming it divine revelation?

Confusing, I know.