Introduction Two young candidates, just beginning their Ph.D. studies in mathematics, were invited to attend the annual meeting of a learned society. As they listened to an extremely complex and abstract lecture on some aspect of mathematical logic, one asked the other, “Do you understand what she’s saying?” “Yes,” was the reply, “I understand what she’s saying. I just don’t know what she’s saying it about.” The student of the Book of Revelation naturally wants to know both what the last book of