It took me a little while to get into this book--the first few chapters were hard work and not much seemed to happen. It was a lot of setting the scene. However, I'd been told by various people that it was really good once you got into it, so I persevered, and I have to say it was worth the effort of getting through the first bit. The descriptions became very involving, and the plot was interesting. It was about, like the title says, the Fall of Lucifer. Mostly using the author's imagination, although some of it comes from the Bible too. The stuff with the DNA was interesting, although rather complicated.
It's a good read if you like fantasy. I haven't read the second yet, I don't know how soon I'll get round to it (or if I will...), but I certainly enjoyed this one.