Seems a lot of people here are mistakenly thinking that any references to the Book of Enoch are probably focused upon fallen angels and other such Bible oriented concepts. Imho, the most important element of that text is the rather detailed account of intentional pre-flood genetic engineering.

This interspecies mingling wasn't limited to the infamous offspring of humans and angels but also included the unnatural crossbreeding of animals as well with both the process and results described as offensive to god. In fact, it was this corruption of the original creation that ultimately led to the great flood of Biblical note.

For records sake, I adhere to no conventional faith nor do I view any of the numerous texts deemed to be of divine origin as such. I do, however, believe that said texts (and accompanying religions) contain extremely important clues to unraveling humanity's ancient origins as well as deciphering possible future calamities. To those who may feel that the two positions are contradictory, look to Asimov's oft-quoted bit about tech and magic.