After launching a series of hardcover anthologies on various science fictional themes in 1966 (with Earthmen and Strangers) for the library market, Silverberg published several anthologies with more literary focuses beginning with Dark Stars in 1969 ("a book of dark dreams for a dark time") and Great Short Novels of Science Fiction in 1970 (composed of long stories that were typically difficult to include in anthologies). Then followed Alpha One in 1970, the first of a series of anthologies intended to "center on no particular theme except that of literary quality." Subsequent volumes appeared at roughly yearly intervals, switching from Ballantine to Berkley with volume 6, and lasting through volume 9. The hardcover Galactic Dreamers is similar in that its focus is on "science fiction as visionary literature" and thus is included in this group.
Most reprinted authors in this group: C.M. Kornbluth (6); James Blish, R.A. Lafferty, and Jack Vance (5 each); J.G. Ballard, Philip K. dick, Fritz Leiber (4 each).