I've never quite understood this book.
There's the objection most nonbelievers have with it, of course: that God allows a man's life to be made hell merely to prove a point. On a whim. A bet with Satan.
The usual reply, though, is that this is to... show us something? I'm not sure, actually, but I assume the usual reply has SOMETHING to do with the book teaching us things.
But what does it teach us?
I've read it at least twice, and each time I am bewildered. The whole deal is set up for a few chapters; Satan rains horrible things upon Job for a little bit; then 80% of the book is Job's friends giving him monologues on the power and glory of God and how God is trying to teach Job stuff.
Then in the last three or four chapters, God comes from the clouds and is like "LOL FRIENDS-OF-JOB, YOU'RE WRONG, STFU, I AM THE LORD WHO IS GREAT." He pontificates on how great he is for the chapters, gives Job some stuff (but doesn't resurrect those killed or anything), then the book ends.
Uh... I just spent 42 chapters learning and studying upon exegeses that WEREN'T EVEN RIGHT? Why INCLUDE so many?! It's like a, I don't know, woodworking book that details for chapter upon chapter on how to make a cabinet, that then ends by saying "but DON'T DO THIS THIS IS WRONG" and not even explaining WHY.
It just confused me.

No offense intended to any Christians; excuse me if the tone is somewhat exasperated.