Apocalypse (from Ancient Greek ἀποκάλυψις (apokálupsis) 'revelation, disclosure') is a literary genre in which a supernatural being reveals cosmic mysteries or the future to a human intermediary. The means of mediation include dreams, visions and heavenly journeys, and they typically feature symbolic imagery drawn from the Hebrew Bible, cosmological and (pessimistic) historical surveys, the division of time into periods, esoteric numerology, and claims of ecstasy and inspiration. Almost all are written under pseudonyms (false names), claiming as author a venerated hero from previous centuries, as with Book of Daniel, composed during the 2nd century BCE but bearing the name of the legendary Daniel.

Eschatology, from Greek eschatos, last, concerns expectations of the end of the present age, and apocalyptic eschatology is the application of the apocalyptic world-view to the end of the world, when God will punish the wicked and reward the faithful. An apocalypse will often contain much eschatological material, but need not: the baptism of Jesus in Matthew's gospel, for example, can be considered apocalyptic in that the heavens open for the presence of a divine mediator (the dove representing the spirit of God) and a voice communicates supernatural information, but there is no eschatological element.

Scholars have identified examples of the genre ranging from the mid-2nd century BCE to the 2nd century CE, and examples are to be found in Persian and Greco-Roman literature as well as Jewish and Christian. The sole clear case in the Jewish Bible (Old Testament) is chapters 7-12 of the Book of Daniel, but there are many examples from non-canonical Jewish works; the Book of Revelation is the only apocalypse in the New Testament, but passages reflecting the genre are to be found in the gospels and in nearly all the genuine Pauline epistles.