The ABC of science fiction

The thought kept popping into my head that Asimov, Bradbury and Clark
would make a GREAT  ABC of science fiction except for the small fact
that  Heinlein is arguably greater than any two of them combined. So
it has to be at least the ABCDEFGH of science fiction. And once you
have gone down that road, you might as well stop at Z for Zelazny.

And then you realize that you have to be an idiot to indulge in such a
gross exercise which has no place for even Bester in  the ABC of the
list. :-)