The author

I, John, your brother and partner in the tribulation and the kingdom and the patient endurance that are in Jesus, was on the island called Patmos on account of the word of God and the testimony of Jesus. -- Revelation 1:9 (ESV)

Some scholars attribute the Book of Revelations to John the Apostle who also wrote the Gospel of John, however the writing style differs:

This has lead some scholars to belief that the book of Revelations was written by someone else, for like John the Elder (also know as "John the Presbyter") who was a huge church leader in Ephesus during the same time. He was mentioned in the writings of Irenaeus and Eusebius, but there is no clear proof that this is the case.

Unique teaching not supported by other scriptures

• There is a blessing on the person who reads the book of Revelations (Revelation 1:3).
• The only book that mentions "the Lord's Day" (Revelation 1:10). This is not to be confused with "The day of the LORD of hosts" which refers to a specific day God will come to judge (Isaiah 2:12; 13:6,9; 58:13; Jeremiah 46:10; Ezekiel 13:5; 30:3; Joel 1:15; 2:11; 3:14; Amos 5:18-20; Obadiah 1:15; Zephaniah 1:7-14; Zechariah 14:1; Malachi 4:5; Acts 2:20) or "The day of our Lord Jesus Christ" which refers to the second coming of Jesus (1 Corinthians 1:8; 5:5; 2 Corinthians 1:14; 1 Thessalonians 5:1-2; 2 Peter 3:10)
• A unique description of the throne room of God (Revelation 4).
• The cosmic battle between Michael and Satan (Revelation 12:7-9).
• The mark of the Beast (Revelation 13:16-18).
• A unique description of the New Heaven and New Earth (Revelation 21:1-5, 22:1-2).
• There is a curse on the person who adds words to the book of Revelations (Revelation 22:18).
• You can lose your salvation if you remove words from the book of Revelations (Revelation 22:19).

Any many more...

Critique

Some people claim that the book of Revelations is a dangerous book that already lead to a lot of violence and fear in the past and continue to cause confusion in the modern Christian life. For example:

• In the 11th-13th centuries, European Christians launched a series of Crusades (military expeditions) to reclaim the Holy Land from Muslim control. They used Revelation to justify these violent campaigns, viewing them as fulfilling God's will and bringing about the end times.
• In 1534, John of Leiden, established a theocratic regime in Münster, Germany, seized control of the city and established a theocratic kingdom based on his interpretation of Revelation. His rule was marked by violence, polygamy, and eventually, a brutal siege by opposing forces.
• From 1618 to 1648, religious and political factors were intertwined, some interpretations of Revelation fueled anxieties and justifications for violence during this European conflict which led to the Thirty Years' War.
• In 1692, although primarily driven by social and psychological factors, some individuals drew upon biblical prophecies, including Revelation, to identify and persecute "witches" during the Salem Witch Trials.
• In 1755, following a devastating earthquake in Lisbon, Portugal, some religious leaders interpreted it as divine punishment for the city's sins. This fueled widespread fear and paranoia, leading to witch hunts and public displays of piety.
• In the 1840s, William Miller predicted the second coming of Christ based on his interpretation of biblical prophecies. This led to widespread excitement and anxiety among his followers, many of whom sold their belongings and prepared for the end of the world. When Christ didn't return as predicted, the movement collapsed, leaving many disillusioned and financially ruined.
• In 1993, David Koresh (the "Messiah"), interpreted Revelation and other biblical texts to justify his religious group's actions during the Waco siege where 76 people were killed including Koresh himself and many of his followers.
• In 1994, during the Rwandan genocide, Hutu extremists used interpretations of the Book of Revelation to demonize Tutsis, claiming they were the biblical "Hamitic" enemies destined to be defeated. This fueled the violence and hatred that led to the deaths of hundreds of thousands of Tutsis.
• In 1997, the Heaven's Gate cult believed that a comet was coming to Earth to take them away to a higher plane of existence. 39 members of the Heaven's Gate cult committed mass suicide in order to be "beamed up" by the comet. The cult members believed that they were fulfilling a prophecy in the Book of Revelation, and their actions led to the deaths of many innocent people.

Jesus himself warned:

"Beware of false prophets, who come to you in sheep's clothing, but inwardly they are ravenous wolves. You will know them by their fruits. Do men gather grapes from thornbushes or figs from thistles?" -- Matthew 7:16

However, some argue that Jesus referred to the prophets' own actions and not his prophecy itself.

Another argument is that these actions are not John's fault, but was caused by human leaders twisting John's prophecies to validate their bad decisions and actions to manipulate followers.

Possible contradictions

How many Spirits does God or Jesus have?

John to the seven churches which are in Asia: Grace [be] unto you, and peace, from him which is, and which was, and which is to come; and from the seven Spirits which are before His throne -- Revelation 1:4 (KJV)

and

And unto the angel of the church in Sardis write; These things saith he that hath the seven Spirits of God, and the seven stars -- Revelation 3:1 (KJV)

and

And I beheld, and, lo, in the midst of the throne and of the four beasts, and in the midst of the elders, stood a Lamb as it had been slain, having seven horns and seven eyes, which are the seven Spirits of God sent forth into all the earth. -- Revelation 5:6 (KJV)

which potentially clash with

[There is] one body, and one Spirit, even as ye are called in one hope of your calling; -- Ephesians 4:4 (KJV)

and

But one and the same Spirit works all these things, distributing to each one individually as He wills. For as the body is one and has many members, but all the members of that one body, being many, are one body, so also is Christ. For by one Spirit we were all baptized into one body — whether Jews or Greeks, whether slaves or free — and have all been made to drink into one Spirit. -- 1 Corinthians 12:12-13 (NKJV)

Possible explanations:

• Some explain that perhaps the Spirit of God has 7 "members" seen as one Spirit, just like the body of Christ is "one body" with many members. But there is no clear proof to confirm this statement.
• Some explain that the number 7 is the symbol of completeness and that John meant, the "complete Spirit of God" and not 7 literally distinct Holy Spirits.

Creatures and 24 elders fell down before Jesus

Now when He had taken the scroll, the four living creatures and the twenty-four elders fell down before the Lamb...

Then the four living creatures said, “Amen!” And the twenty-four elders fell down and worshiped Him who lives forever and ever.

-- Revelation 5:8,14 (NKJV)

which clash with Jesus own words:

And Jesus answered him, “It is written, ‘You shall worship the Lord your God, and Him only...’ ” -- Matthew 4:10 and Luke 4:8

which is a quote from:

Samuel said to all the house of Israel, “If you are returning to the Lord with all your heart, then put away the foreign gods and the Ashtaroth from among you and direct your heart to the LORD (Yahweh)* and serve Him only, and He will deliver you out of the hand of the Philistines.”

So the people of Israel put away the Baals and the Ashtaroth, and they served the LORD (Yahweh)* only.

-- 1 Samuel 7:4

Possible explanations:

Revelation 5:8-14 is a build up of different events and not a mixture of one worship event to the Lamb. "fell down" could mean "worship" but often only means showing respect to a king. In this case John specifically only mentions "worship" in verse 14. The "Him" of verse 14 is actually referring to God and not the Lamb because in this context:

• God is not the Lamb as they interact with each other as separate persons (Revelation 5:6-8)
• One "sat on the throne" (Revelation 4:2), not a trinity and not God with the Lamb
• The Lamb "stood" (Revelation 5:6) and God "sat" (Revelation 5:7)
• The Lamb was "in the midst of the elders" (Revelation 5:6) and God "on the throne" (Revelation 5:7)
• God is described as the "Ancient of Days" in a vision of the prophet Daniel which could refer to "Who lives forever and ever" which is translated by the Interlinear translation as "Who lives for the ages of the ages".

Timing of Christ's return

Then he said to me, “These words are faithful and true.” And the Lord God of the holy prophets sent His angel to show His servants the things which must shortly take place. “Behold, I am coming quickly!" -- Revelation 22:6-7 (NKJV)

which potentially clash with

But, beloved, do not forget this one thing, that with the Lord one day is as a thousand years, and a thousand years as one day. The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish but that all should come to repentance. -- 2 Peter 3:8-9 (NKJV)

However, if you continue reading...

But the day of the Lord will come as a thief in the night, in which the heavens will pass away with a great noise, and the elements will melt with fervent heat; both the earth and the works that are in it will be burned up. -- 2 Peter 3:10 (NKJV)

A possible explanation is that John meant by "quickly" that the Lord comes unexpectedly, instead of soon, as we know more than a thousand years have already passed since this prophecy was written.