The Book of Enoch is any of several pseudepigraphal works that attribute themselves to Enoch, the great-grandfather of Noah; that is, Enoch son of Jared (Genesis 5:18). A piece of ancient literature is a pseudepigraphon if it makes false claims as to authorship. A pseudepigraphon will purport to have a (usually well-known) author, but its claims are unfounded.
Enoch is also one of the three people in the Bible taken up to heaven while still alive (the only others being Elijah and Jesus). We read about Enoch’s translation in Genesis 5:24: “And Enoch walked with God, and he was not; for God took him” (see also Hebrews 11:5). Most commonly, when people refer to the Book of Enoch, they mean 1 Enoch, which is wholly extant only in the Ethiopic language. The Book of Enoch is accepted as canonical by the Coptic Church in Ethiopia and the Eritrean Orthodox Church. In addition to 1 Enoch, there are 2 Enoch (“The Book of the Secrets of Enoch”) and 3 Enoch (“The Hebrew Book of Enoch”). Fragments of the Book of Enoch in Aramaic and Hebrew were found among the Dead Sea Scrolls.
Much of the Book of Enoch is apocalyptic—it uses vivid imagery to predict doom and the final judgment of evil. There’s a heavy emphasis on angelology and demonology, and a large portion of the book is devoted to filling in the backstory of Genesis 6:1–4. The Book of Enoch thus explains the origin of the Nephilim and the identity of the “sons of God,” mentioned in Genesis 6:2 and 4. The result is a strange and sensationalistic piece of non-canonical literature.
In its Ethiopic form, the Book of Enoch is arranged in five sections:
Section I (chapters 1—36) has Enoch pronouncing God’s judgment on the angels who cohabited with the daughters of men (see Genesis 6:1–4). In this section, two hundred angelic “Watchers” rebel against God and are cast out of heaven along with Satan. On earth, they indulge their lust and have sexual relations with human women, producing the Nephilim, a race of evil giants who terrorize the antediluvian world. Enoch sees a “chaotic and horrible” place and a fiery prison reserved for the angels who sinned (Enoch 21:3, 7).
Section II (chapters 37—71) has three parables relating apocalyptic judgments. It also contains the story of Enoch’s translation into heaven (see Genesis 5:24). In this section, Enoch describes the activity of an angel named Gadreel: “He it is who showed the children of men all the blows of death, and he led astray Eve, and showed [the weapons of death to the sons of men] the shield and the coat of mail, and the sword for battle, and all the weapons of death to the children of men. And from his hand they have proceeded against those who dwell on the earth from that day and for evermore” (Enoch 69:6–7, trans. by Charles, R. H., 1917).
Section III (chapters 72—87) is primarily an explanation of the workings of the stars in their pathways, as per a vision that Enoch has.
Section IV (chapters 88—90) contains Enoch’s vision of the coming flood and prophecies concerning other events yet future, including the Exodus, the conquest of Canaan, the building of the temple, the fall of the northern kingdom, the destruction of Jerusalem, the final judgment, the building of the New Jerusalem, the resurrection of the saints, and the coming of the Messiah.
Section V (chapters 91—105) pronounces woes on sinners and promises blessings to the righteous. It ends with a promise of peace to the “children of uprightness” (Enoch 105:2).
The biblical book of Jude quotes from chapter 1 of the Book of Enoch in Jude 1:14–15, “Enoch, the seventh from Adam, prophesied about these men: ‘See, the Lord is coming with thousands upon thousands of his holy ones to judge everyone, and to convict all the ungodly of all the ungodly acts they have done in the ungodly way, and of all the harsh words ungodly sinners have spoken against him.’” Jude’s quotation does not mean the Book of Enoch is inspired by God or that it should be in the Bible.
Jude’s quote is not the only quote in the Bible from a non-biblical source. The apostle Paul quotes Epimenides in Titus 1:12, but that does not mean we should give any additional authority to Epimenides’ writings. The same is true with Jude 1:14–15. Jude quoting from the Book of Enoch does not indicate the entire Book of Enoch is inspired, or even true. All it means is that particular passage of Enoch is true. It is interesting to note that no scholars believe the Book of Enoch to have truly been written by the Enoch in the Bible. Enoch was seven generations from Adam, prior to the flood (Genesis 5:1–24). Evidently, though, the words Jude quotes were genuinely something that Enoch prophesied—or the Bible would not attribute it to him: “Enoch, the seventh from Adam, prophesied about these men” (Jude 1:14). This saying of Enoch was somehow handed down through the generations and eventually recorded in the Book of Enoch.
We should treat the Book of Enoch (and the other books like it) in the same manner we do the other apocryphal writings. Some of what the Apocrypha says is true and correct, but much of it is false and historically inaccurate. If you read these books, you should consider them interesting but fallible historical documents, not as the inspired, authoritative Word of God.