Amazon.com: Luce and Daniel's story is very romantic. What inspired you to write a love story between a human and an angel?
Lauren Kate: I’ve been writing love stories for as long as I’ve been writing. To me, the most complicated romances make the most interesting narratives, so I’m always looking for new obstacles to throw in my lovers’ paths. When I was getting my masters degree in fiction, I was studying biblical narratives and came across a line in Genesis (6:1-4), which describes a group of angels who fell in love with mortal women. Putting this reference together with a mention in Isaiah and another in Palsm 82, biblical scholars conclude that these angels were actually cast out of Heaven for their lust. Which means--you could say--that these angels chose love over Heaven. I found this to be an endlessly interesting set up for an incredibly complicated romance. I started thinking about what kind of mortal girl it would take to attract an angel’s attention. And what it would be like for her to find herself in this position. What kind of baggage would an angel have? What would her very over-protective parents think? From there, this whole world unfurled in my head with fallen angels, demons, reincarnation, and the war between good and evil all battling for a piece of the action.

Amazon.com: We've been wondering about the "mechanics" of Luce and Daniel's story (for lack of a better word). Does Daniel age? Or does he stay seventeen forever (while Luce grows older)? And with that said, what does he do while Luce is growing up in each of her lives? What was he doing before he met Luce in this life?
Kate: What’s important about angels is not their bodies but their souls. In their purest forms, they’re actually genderless, but for my story to work--for the angels to come down to earth and interact with mortals--they all assume human bodies and attach themselves to human genders. Daniel is eternal and will live on forever, but the body Luce sees him in (gorgeous as it is) is really just a shell for the soul that she loves. There’s not the feeling of a ticking clock in the background as there might be with, say, a vampire story. Right now I’m writing Passion, the prequel where we’ll see Luce and Daniel in a dozen other lifetimes, so I’m exploring a lot of these mechanics (a great word for it, by the way) between the angel’s bodies and souls.

The way Daniel occupies himself in between Luces varies from life to life. His soul is least at rest just after she’s died, before she’s incarnated into another life--when she is “in between.” During her lives, even when he isn’t with her, he is always aware of her age, what she’s going through, how she’s doing. He has a sort of internal Lucinda clock. Sometimes he meets her as a child, sometimes he tries to stay away from her as long as possible, to give her as much of a life outside of him as he can. In the years leading up to the life where they meet at Sword and Cross, Daniel was living on Skid Row in Los Angeles.

Amazon.com: Fallen and Torment talk a lot about the history of Heaven and Hell, the different classes of Angels, and the rules of human-angel interaction. Obviously these themes are explored heavily in religious texts, but were there other sources that informed your story?
Kate:It’s interesting because there is actually very little in the Bible about angels--a few mentions in the Old Testament, a few more in the new. And the mentions that we do have are often vague or contradictory. Most of what we think of when we think of angels today -- From Amazon.com Amazon.com Review