The book of Revelation is unique in a number of ways, and one of those ways is how it takes three different genres and combines them into a single book. Revelation employs prophecy, apocalyptic, and the form of a letter for John to make his point. As an apocalyptic book, Revelation concerns visions that are given to John that deal with the divine, transcendent reality, and how that reality is relevant for our world today. It gives a divine perspective on the world, and shows us something of where history is going. As a prophetic book, John writes with the very authority of God himself, meaning the words that John writes are true. They are absolutely true in the way that God is, himself, truth. And the categories of apocalyptic and prophetic are very closely united in Revelation, as they are, for example, in a book like Daniel in the Old Testament. But thirdly, Revelation is communicated in the form of a circular letter. This is a letter that was sent around to more than one church. And as a letter, Revelation was relevant for churches even in the first century. And it's important to remember that it was a letter, that Revelation is not only about what might happen thousands of years in the future, but Revelation, as it was originally, was given, was written to specific churches in the first century. And whatever else John might be doing, his message of Revelation is relevant for those first-century churches. And so in some senses, Revelation is unique in being a prophetic apocalypse that was sent around to churches in the form of a circular letter. It combines all three of those genres.