It is a belief that they are three seperate beings, yet they work together with one purpose.
Romans 8:38 says "Nor height, nor depth, nor any other creature, shall be able to separate us from the
love of God, which is in Christ Jesus our Lord."
Also Acts 7:55-56 says "But he, being full of the Holy Ghost, looked up stedfastly into heaven, and saw the glory of God, and
Jesus standing on the right hand of God, And said, Behold, I see the heavens opened, and the
Son of man standing on the right hand of God."
Here's what I've found on Revelation:
There are many conflicting sources. What is basically believed by historians, archeologist, etc. is that it could have been written either around 60 AD under Nero, or between about 90 and 92 AD under Domition. Long story short, it is primarily believed to be either during the same time, or just after, yet still before many of the other books.
-D