Professed Christians only, please. Do you know about this key to understanding the book of Revelation?

I agree with you that Revelation should be read with a knowledge of the OT, but that really applies to all the books of the NT, don't you think? Everything in the Bible should be read in light of everything else, in other words, one shouldn't take one verse or group of verses and, for instance, make up a whole new doctrine or way of thinking.