That was superb.

I wasn't too sure when I started reading this, but Northern Lights works on multiple levels. On one hand, much of the plot revolves around a chase through an increasingly mysterious fantasy tinged environment which, even with the darkness of the ending, is clearly aimed at a YA audience.

However, embedded in the world-building and in the motivations of the various characters is a deeper exploration of the way in which religion -- when given too much power -- both corrupts and harms those who fall under its influence.