One of the most important non-canonical apocryphal works, The Book of Enoch, was written during the second century B.C.E. and is probably a huge influence on early Christian, particularly Gnostic, beliefs. It is filled with hallucinatory visions of heaven and hell, also, angels and devils. Enoch introduced concepts such as fallen angels, the appearance of a Messiah, Resurrection, a Final Judgement, and a Heavenly Kingdom on Earth.
First of all, The Book of Enoch was extant centuries before the birth of Christ and yet is considered by many to be more Christian in its theology than Jewish.
Chapter 1 – Book of Enoch
1 The word of the blessing of Enoch, how he blessed the elect and the righteous, who were to exist in the time of trouble; rejecting all the wicked and ungodly. Enoch, a righteous man, who was (1) with God, answered and spoke, while his eyes were open, and while he saw a holy vision in the heavens. This the angels showed me.
(1) N.B. The italicized words supply a gap in the text.
2 From them I heard all things, and understood what I saw; that which will not take place in this generation, but in a generation which is to succeed at a distant period, on account of the elect.
3 Upon their account I spoke and conversed with him, who will go forth from his habitation, the Holy and Mighty One, the God of the world:
4 Who will hereafter tread upon Mount Sinai; appear with his hosts; and be manifested in the strength of his power from heaven.
5 All shall be afraid, and the Watchers be terrified.
6 Great fear and trembling shall seize them, even to the ends of the earth. The lofty mountains shall be troubled, and the exalted hills depressed, melting like a honeycomb in the flame. The earth shall be immerged, and all things which are in it perish; while judgment shall come upon all, even upon all the righteous:
7 But to them shall he give peace: he shall preserve the elect, and towards them exercise clemency.
8 Then shall all belong to God; be happy and blessed; and the splendour of the Godhead shall illuminate them.