Although most people do assume that the Apostle John, or John the Evangelist,wrote the Book of Revelation, it is not really the consensus of opinion among biblical scholars. Of the man who wrote the Book of Revelation, Wikipedia says:
"The author of the Book of Revelation identifies himself as "John." Traditionally, this named author is believed to be the same person as both John the apostle of Jesus and John the author of the Fourth Gospel. The early 2nd century writer, Justin Martyr, was the first to equate the author of Revelation with John the Apostle. However, some biblical scholars now contend that these were separate individuals.
"John the Presbyter, an obscure figure in the early church, has also been identified with the seer of the Book of Revelation by such authors as Eusebius of Caesarea and Jerome."
So the issue of who the author of Revelation was is not a simple one. Personally, I believe that we can go a long way in deciding this for ourselves if we study the actual content of various works that are attributed to him. This content is called internal evidence. It includes the Gospel According to John and the Johanine Epistles (John I, II and III). The second and third epistles of John are short and in general they repeat what is said in detail in his first epistle, but there are two characteristic phrases that he says more than once. Both of these need our attention.
The first is that John does use the phrase "the antichrist." He describes anyone who preaches a false Christian doctrine as an antichrist. However, because of his usage, translators do not choose to capitalize the word, as we do see in evangelical writings and also in the Book of the Revelation. By the time Revelation was written there was a concept drifting through the Church that there was such a thing as an Antichrist that was going to mount an attack on the Church, or on believers all through the known world (which was the Roman Empire).
If you read the three epistles of John, you find that he does not seem to live in fear of a great evil Antichrist, but rather that he regards it as our duty to refute the preaching of an antichrist when we come across one, or when an apostate or former Christian is preaching to us. He urges his friends to do so. The second thing that illuminates John's letters is his concept of love as expressed by Jesus' life and death. He writes:
"Dear friends, let us love one another, for love comes from God. Everyone who loves has been born of God and knows God. Whoever does not love does not know God, because God is love. This is how God showed his love among us: He sent his one and only Son into the world that we might live through him. This is love: not that we loved God, but that he loved us and sent his Son as an atoning sacrifice for our sins. Dear friends, since God so loved us, we also ought to love one another. No one has ever seen God; but if we love one another, God lives in us and his love is made complete in us.
"This is how we know that we live in him and he in us: He has given us of his Spirit. And we have seen and testify that the Father has sent his Son to be the Savior of the world. If anyone acknowledges that Jesus is the Son of God, God lives in them and they (live) in God. And so we know and rely on the love God has for us.
"God is love. Whoever lives in love lives in God, and God in them. This is how love is made complete among us so that we will have confidence on the Day of Judgment: In this world we are like Jesus. There is no fear in love. But perfect love drives out fear, because fear has to do with punishment. The one who fears is not made perfect in love.
"We love because he first loved us. Whoever claims to love God yet hates a brother or sister is a liar. For whoever does not love their brother and sister, whom they have seen, cannot love God, whom they have not seen. And he has given us this command: Anyone who loves God must also love their brother and sister." [I John 4:7-21]
That passage represents what I would call the overriding message that John had for the world after growing up as a member of Jesus' family. He is believed to have been Jesus' cousin, and it is also thought that he lived into his old age and died somewhere other than Jerusalem. A community grew up around him and their writers produced the Gospel According to John; it is referred to as the Johanine Community. Unfortunately for us, scholars on the level of Bishop John Shelby Spong now believe that none of the Gospels was written by an eyewitness, but rather they were produced by the communities in which the Apostles ended their lives (in a timely or untimely manner). So in short, John did not write John, so to speak.
The passage above, while beautiful, is not as popular as the short declaration he made that is of paramount importance to the Christian faith. It contradicts the evangelical preachers who are in bed with Teabaggers who want Americans to starve in the streets because of the perceived moral defects that they believe produce poverty. John says:
"My dear children, I write this to you so that you will not sin. But if anybody does sin, we have an advocate with the Father—Jesus Christ, the Righteous One. 2 He is the atoning sacrifice for our sins, and not only for ours but also for the sins of the whole world." [I John 2]
This passage has specific importance in relation to social conditions today, and it also provides refutation of the position of the Book of Revelation, which has many odious passages describing God's supposed punishment of innocent people, animals, children and unborn babies because of some kind of "sin." I would like to know just what sin the whole world is committing right now that merits this so-called Tribulation.
We know that the major part of the world’s people is simply living everyday lives, as Jesus said in the Sermon on the Mount: eating and drinking, giving in marriage, etc. They are rearing their children, working for a living--but suddenly God is going to appear in a terrible rage and begin beating them up. I repeat: what have they done to deserve this?
That is what I mean by internal evidence. I do not believe that the person who wrote what I quote above was the same man who visualized Jesus with a sword or a spear in his hand; most scholars today do not believe that either.
There is another piece of evidence that discourages the belief that John the Evangelist wrote Revelation. He is said to have been exiled to the island of Patmos--or at least the author of Revelation was--during the reign of the Emperor Domitian. Wikipedia says of him:
"Domitian (Latin: Titus Flavius Caesar Domitianus Augustus; 24 October 51 – 18 September 96) was Roman emperor from 81 to 96. Domitian was the third and last emperor of the Flavian dynasty."
If Domitian assumed the throne of the Empire in Year 81 C. E., that does not mean that John of Patmos was exiled that very year. It could have been as late as 96 C. E., which pretty much guarantees that even the long-lived John the Evangelist would have passed away by that time. It is stretching it if you want to believe that John the cousin of Jesus lived that long. Furthermore, after the destruction of the Second Temple of Jerusalem in 70 C. E., Jewish political activity had ebbed to a very low level; in fact, it is believed that John did not actually end his life there.
It seems to me that John would have been living in a town somewhere. established within a community of the emerging Church where he could be cared for. Traditionally it is also assumed that Jesus charged John to assume the care of Mary his mother, and by the time of his death we may assume that Mary, too, had passed away. So that places John's life in a context that makes it unlikely, I think, that he ended up in Patmos.
The Gospel of John also contains a lot of Neo-Platonic philosophy that contradicted Orthodox Judaism, which was the faith that virtually all of Jesus' community observed. As Jesus was growing up, everybody kept Kosher and observed the Law as it had evolved in Late Antiquity. People were still being stoned once in awhile, as the story of the early martyr St. Stephen recounts. But even with its Platonic influences, the Gospel of John does not agree with the hate and rage that the Book of Revelation is eaten up with from the beginning to the end. Internally, it fails to match with what John wrote under his own hand.
It is also my personal opinion that Revelation should not be in the Canon of Scripture, precisely because its content is so un-Christian. The people who maintain that it was written by John the Evangelist have lent it credibility with that assertion, but internally, it is completely out of harmony with the other four works that were written by the Evangelist. The Book of Revelation is ugly and political, ringing false to Christianity. It has produced no "good fruits" and I believe that in reality the Church has no real use for it. The misuse that it has been subjected to in the evangelical community is also good and sufficient reason to dismiss it from consideration in Christian theology.