" If you don’t run with this crowd, you might assume that SF is an abbreviation of Science Fiction. But here it means Speculative Fiction. This coinage is a way to cope with the problem that Science Fiction is mysteriously, inextricably conjoined with the seemingly unrelated literature of Fantasy. Many who are fond of one are fond of the other, to the point where they perceive them as The Same Thing in spite of the fact that they seem quite different to non-fans. "

― Neal Stephenson , Some Remarks: Essays and Other Writing