Another of those odd but agreeable science fiction/nonfiction hybrids: 18 pieces, 196793, drawn from various publications and comprising nine stories, six essays, a play, and two unquantifiable entries. As noted before in these pages, Anderson's a superb practitioner of short- and medium-length stories, while his novels have generally disappointed. The themes here show to good effect his eclectic interests, probing intelligence, and visionary approach, with tales about alien contact, the end of the universe, alternate worlds, an inn unlocated in space or time whose guests range from the historical to the imaginary, the Old Stone Age, the last wilderness, ESP, God, and interstellar voyagers. No less fascinating are the essays, which feature, variously, legendary Astounding/Analog editor John W. Campbell, Jr., the Voyager flyby of Neptune, possible future societies, Rudyard Kipling, the little- unknown Danish fantasist Johannes V. Jensen, and an essay that brilliantly bestrides the border between science fiction and the philosophy of science. ``Rokuro'' is a N play of the future. And of the fiction/nonfiction pieces, one is an amusing biography of the imaginary Karl Wolfram, who, in another reality perhaps, discovered the element that bears his name; the other, a tremendous tour de force by any standard, introduces atomic theory--in modern Anglo-Saxon! ``Having the same number of bernstonebits, the samesteads of firststuff behave almost alike minglingly'' not only makes sense but is a measure of true genius. The fiction's excellent--but it's impossible to begin any of these nonfiction entries without immediately becoming utterly engrossed.