Jaws of Darkness by Harry Turtledove.

I just finished the book and give it 5 out of 5 stars. It's another masterpiece by Harry Turtledove and a must read for fans of his books.

It's part of a series though and newbies should try to hunt down the first book and start reading.

A brief review:

It's about a war on a continent and like most Harry Turtledove books is a what-if situation gone out of hand. What if there were no such things as planes, tanks and atomic bombs during WWII. No persecution of Jews, no Pearl Harbour. Instead replace these with a fantasy setting, where dragons fly and behemoths role past defenses. Instead of an atomic bomb which kills thousands, a vile sorcery that uses the life-blood of thousands to fuel itself in the attepmt to murder even more. That's the basic setting, and if you are interested try to get your hand on the book and be engrossed.