 Susanna Clark spent 10 years working on her first novel and it is an epic. It's about two genius Englishmen who approach the subject of mythological magic as a science in an effort to bring magic back to the world. It's an alternate history set around the year 1800. It is very long, but I don't recall ever feeling that it got slow or tedious. These two characters, they start out as colleagues and they become competitors. They have very different ideas about how the subject of magic should be approached and of course they discover there are some very high prices to pay for what they are doing. Whether you consider this book science fiction or fantasy is immaterial. It's just a good book and I give it my highest recommendations.