The sixth anthology from Isaac Asimov's Science Fiction Magazine--with one short-short, two poems, and twelve stories ranging from the excellent to the YA-ishly trivial. The best: James Tiptree Jr.'s vivid ghost story set on an authentic-sounding Yucatan coast; Rand B. Lee's fascinating, original yarn about an all-male group of castaways obliged to clone themselves to survive; and Ted Reynolds' comic piece on the pitfalls of an alien-exchange program. More ordinary offerings come from Gregory Benford (colliding black holes), Gene Wolfe (unicorns and recombinant DNA), and Joan D. Vinge (dragons); there are time-travel variations on the London Blitz and ancient Rome, as well as Barry B. Longyear's Nebula-winning alien contact novella, ""Enemy Mine."" And sketchiest of all are bits by Asimov (space colonies), Elizabeth A. Lynn (post-nuclear holocaust), and Robert Silverberg (a cozy bar that no one ever leaves). In sum: the sf gamut from brilliant to vapid--but certainly worth a browse by short-story fanciers.