The word ‘apocalypse’ means a ‘revelation’ or ‘unveiling’, so an apocalyptic book claims to reveal things which are normally hidden or to reveal the future. The Jewish Apocalyptic books belong approximately to the period from 200 bc to ad 200 and deal with the end of the present order or with the next world.
Apocalyptic literature proper begins with the Book of Daniel, probably written during the persecution of Antiochus Epiphanes (175–164 bc), though there are apocalyptic tendencies in some of the prophetic writings with their references to the approaching ‘day of the Lord’. The Apocalyptic writings are almost always pseudonymous and written in the names of Israel's past heroes. The Jewish Apocalyptic writings outside the OT include 1 and 2 Enoch, Baruch II, 4 Ezra (2 Esdras), the Assumption of Moses, Jubilees, the Ascension of Isaiah, and the Testaments of the Twelve Patriarchs. The main Christian Apocalypses are Revelation and the (non-canonical) Apocalypse of Peter.