What worries science-fiction writer Vonda McIntyre about genetic engineering is not just the possible creation of alien microbes—it's the loneliness of the human spirit caught in biological traps.

In "Fireflood and Other Stories" McIntyre explores a world of futuristic technologies built out of flesh and psyche—instead of "Stars Wars" electronics. For example, in the title story the central character is a woman physiologically reconstructed so that she is adapted to mining on Mars: She has become a clawed, armor-plated, slow-breathing body with a human inside….

Taken separately, some stories in this collection are weaker than others. They seem to be laboratory experiments in themselves—the author's attempt to explore a particular biological invention or human remake.

Other stories—notably "The Mountains of Sunset, the Mountains of Dawn," "Screwtop," "The Genius Freaks," as well as "Aztec"—achieve an effect all too rare in science fiction: Instead of...