“Genre” has to do with what type of literature describes a work or writing. There are four options for the Book of Revelation: Prophecy, epistolary literature (that is, a letter), apocalyptic (in which heavenly truths are revealed through symbolism), or, a combination of the previous three (the view I espouse).
Classical and Revised Dispensationalists tended to see Revelation as prophecy rather than apocalyptic or as epistolary literature and therefore interpreted it almost wholly in a futurist manner. This was driven mainly by the dispensationalist program which sees two plans of God, one for Israel and another for the (largely Gentile) church. Since the program for Israel is unfulfilled, the future is seen as the time when the prophecies of the OT will be completed. The seventieth week of Daniel is seen as yet unfulfilled and elements of the Revelation are connected with the events of the seventieth week and then the bulk of these events are placed largely after the secret rapture of the church. The purpose is so that God can finish his unfulfilled program for Israel.
This interpretive scheme (and I do not use the word “scheme” in any negative sense) was backed up with facts that may or may not be relevant, such as that the word “church” is not used after chapter 3, and by ignoring or failing to see the significance of similar facts that may be relevant, such as that the word “Israel” is only used twice after chapter 2 and one of those is in the New Heavens New Earth section (21:12).
Holding to this view of Revelation’s genre exclusively fails to take into account evidences in the text regarding other genres such as epistolary literature (since the visions occur in the context of letters to seven churches) and apocalyptic literature (evidenced through the use of heavenly messengers and symbolic visions to communicate messages regarding the spirit world’s interaction with this realm). While there is, no doubt, prophecy in the Revelation, this is not the exclusive view one should take with this writing.