Angels And The Book of Enoch

Angels have been mentioned in the Bible, but they are seen in extra-Biblical sources as well. One such place is the Book of Enoch and this book is mentioned in the Bible so it has some credibility based on that. However, can we trust the book for more than just the portions that made it into the Bible?
We will also look at other topics such as the preincarnate instances of Jesus and that are often confused with angels.