They often were sent to other people to help explain Christianity. Sometimes they were written to counter heresy, or wrongful interpretations of the teachings of Jesus. This book was written by John about 1900 years ago. He was shown visions of the future by Jesus. This book contains many prophecies about the End Times, or the Apocalypse.
Many bookstores sell copies of the Bible.
We recommend a Bible with footnotes that explain the meaning of different Bible passages.