Alert readers expect a certain amount of bombast from editors of "best of" anthologies; but, as Asimov remarks in his introduction (his emphasis): "I don't know any great scientists who are great science fiction writers." The by-line is similarly elastic, including "scientists" "who obtained the education to become such, but drifted away." It's not even an original idea for an anthology. And so to the contents: 21 stories, 1954-85, except for one turn-of-the-century antique, a sort of talky prototype of Borges' "The Library of Babel," from Kurd Lasswitz. The better, well-known entries include: Arthur C. Clarke's space race in ships propelled by solar sails, "The Wind from the Sun"; J.F. Bone's masterful tale of amoeba-like aliens (Martians?) encountering an enigmatic (NASA?) space probe; James V. McConnell's thin but original look at experimental psychology from the rat's viewpoint; "Love is the Plan the Plan is Death," James Tiptree Jr.'s powerful tale of loving, cannibalistic aliens struggling to cope with a deteriorating climate; and from Chad Oliver, a strong humans-really-come-from-outer-space yarn, "Transfusion." The remaining tales feature some fair ideas in often lifeless treatments: tiny, super-dense aliens; a space elevator; a cyborg spaceship; linguistic problems; involuntary population control; historical fantasies; witches; and hyperspace. A few goodies, then, but generally mediocre and disappointing.