The Rise and Fall of the Nephilim gives a great account of the mysterious 'watchers', the ones who were called the sons of god who looked upon the daughters of man, which apparently started all the vice on Earth. It's not much of a stretch to speculate that lust for the beautiful earth women is what caused the downfall of even the 'sons of god', because lust seems to be what drives our society even now. Just look at advertising, or a Victoria Secret catalog and you'll see that lust is what drives us to buy-buy-buy, and can even bring down a president.
Scott Alan Roberts pulls together the threads of the story by way of Biblical references, where he certainly knows his subject. While apologizing way too much for stepping on the toes of believers, in my humble opinion, Roberts shows how the passages of the Bible, and the Book of Enoch can be made much clearer if you insert real beings for the 'watchers', instead of angelic beings. This makes sense, since imagining a being made of spirit, giving up his lofty position just for sex, does seem a bit silly.
Pros: Roberts gives up a great Biblical background to the Nephilim, and even includes the ancient astronaut theories. He includes Stichin's theories, giving us background into how the translations were amiss. I can't vouch for that since I don't read ancient languages, or more than one modern one for that matter.
Cons: I didn't feel as if I learned anything new with this book, though I had just been reading The Genius of the Few, by Christian & Barbara Joy O'Brian, two authors who define this research.
Roberts does back up his work with a very thorough, notes, bibliography and an appendix which will come in handy to fellow researchers. This book is a good introduction to the subject of the Nephilim.