BOOK REVIEW : ‘Murasaki’: A Peculiar, Plausible World : MURASAKI.<i> edited by Robert Silverberg and Martin H. Greenberg</i> . Bantam. $20, 304 pages

The vast majority of science fiction novels and short story anthologies never attain the velocity necessary to escape the hermetic world of the genre’s fans. “Murasaki” is clearly intended to be an exception.

But although its premise is clever--six Nebula Award-winning science fiction writers create independent stories evoking a “shared world”--only one of the stories emits much heat and light.

The authors’ “shared world” is actually two Earth-like planets revolving around Murasaki, a sun-like star named after a medieval Japanese fiction writer. The two planets are something like the Earth and the Moon, for they orbit around each other as they orbit their sun. But they are closer to the same size, so they face each other while rotating on a common axis between them.

This peculiar but plausible arrangement, the authors imagine, permits relatively easy travel between the two planets, which are named after the medieval Japanese author’s two most popular characters, Genji and Chujo.

As the heavenly bodies’ names might suggest, the Japanese play a central role in the book. The action consists in part of a space race from Earth to the Murasaki system, which is 20 light years away by star ship. The superbly equipped, deliberate Japanese are pitted against the mercurial Scotch tape-and-baling-wire Americans.

The contributors to this anthology began to conceive their stories after reading the same scenario: a fairly detailed sketch of the plot, characters and settings and a detailed technical description of the atmosphere, geology and natural history (including that of the “sentients,” or creatures blessed with some degree of intelligence) of the planets Genji and Chujo. This scenario appears in its entirety (60 pages of small print) as an appendix to the book.

Five of the six writers who contributed to “Murasaki” are known to buffs as purveyors of “hard” science fiction, meaning they take pains to make their fiction as scientifically plausible as possible.

Murasaki, for example, is based on a star that actually exists (although unnamed by astronomers); the authors dutifully list the star’s catalogue number and astronomical location. That the star actually has any planets is, however, highly doubtful.

Helping to keep the group’s astrophysics plausible is contributor Gregory Benford, a physics professor at UC Irvine. The remaining four “hard” science fiction writers are venerable war horses Frederik Pohl and Poul Anderson, who wrote the scenario for the book, and younger writers David Brin and Greg Bear.

The only contributor whose previous work places her outside the category of hard science fiction is fantasy writer Nancy Kress, who supplies the volume’s final story. In that whimsical tale she manages to provide a surprise ending that pulls together some of the loose strands left by her colleagues.

What sets her apart most sharply from the others, though, is that she focuses primarily on intimate feelings, not on how nature works on other planets.

Although Kress’ exploration of relationships among humans and other “sentients” is sensitive, readers unused to the conventions of hard SF (for example, techno-adventure with lots of scientific detail) may find this volume deficiently attentive to matters of the heart. What motivates the characters in “Murasaki,” for instance, is not always clear. The reader may wonder why the men and women choose to spend most of their adult lives crammed into a tin can hurtling through space, only to endure even more unspeakable terror and deprivation upon landing.

Many of the characters seem little more than cardboard figures inside their space suits--the Americans resemble displaced cowboys and cowgirls, and the Japanese men and women seem to be imitating medieval samurais. They bow to peers at 15-degree angles (45 degrees for superiors) and remain otherwise inscrutable.

Nevertheless, the anthology contains one story whose characters are sympathetic, whose theme is compelling and whose execution is memorable--as much so as anything this reviewer has seen in today’s mass-market fiction.

In fact, the story’s hero rises well above most in that genre, for he is both noble and believable. The story--Anderson’s “Language”--is the most imaginative and human improvisation on the “Murasaki” theme. The other contributions glow in its reflected light.

Next: Jonathan Kirsch reviews “Center Stage: A Biography of Helen Gahagan Douglas” by Ingrid Winther Scobie (Oxford) .