While this is a solid, oftentimes engrossing piece of supernatural fiction, this is not a Science Fiction novel. I was certain it was, since it won the Nebula Award for best novel. About 100 pages in, however, I was a little disappointed that it wasn't. But it is extremely well-written and all the characters are realistic, even as one in particular is quite insane. This is a story where modern archaeology clashes with ancient mythology through space-time. That may sound like Science Fiction, but this book feels more like fiction with touches of fantasy shown through a woman's mind thoroughly baked in the Yucatan sun. All in all, this is a good book with interesting characters and writing so good that it flows along unnoticed until you find yourself somehow turning the final page. Take care.