SCIENCE FICTION IN BRIEF : DEATH QUALIFIED: A Mystery of Chaos <i> by Kate Wilhelm (St. Martin’s Press: $22.95; 448 pp.).</i>

Kate Wilhelm’s engrossing new novel defies categorization. A courtroom drama, mystery and science-fiction thriller, its philosophy is perhaps best summarized by this comment from one of its characters: “Nothing’s isolated, nothing. It’s all connected.”

Lucas Kendricks escapes from a scientific-research project where he has been imprisoned for seven years under heavy sedation. The moment he returns home to Oregon, one step ahead of mysterious pursuers in search of missing computer disks, he is killed. His wife, Nell, is charged with the murder. Barbara Holloway, a lawyer who is “death qualified”--licensed to defend clients accused of capital crimes--is drawn reluctantly into Nell’s case. But nothing is as clear-cut as it seems, and reality shifts regularly and subtly.

A master of characterization, Wilhelm crafts multidimensional personalities whose strengths and weaknesses are revealed gradually and tantalizingly. All of Wilhelm’s women, whether hero or villain, are independent and self-sufficient; the men often are appealingly non-sexist. Her narrative painlessly teaches us the rudiments of chaos theory, the butterfly effect and other discoveries integral to its challenging climax--a climax that leaves the reader hungering for another Wilhelm novel.

Sensitive, thought-provoking and involving, “Death Qualified” is an unqualified success.

THE DARK BEYOND THE STARS by Frank M. Robinson (Tor Books: $19.95; 416 pp.) .

Thirty-five years after writing his classic superman novel “The Power,” Frank M. Robinson (co-author of “The Glass Inferno”) returns to science fiction with this generation-ship masterpiece.

Earth’s only interstellar exploration spaceship, the Astron, has served 2,000 years and 100 generations under the firm hand of nearly immortal Capt. Michael Kusaka, who has been programmed not to return to Earth until he finds evidence of other life in the universe. After exploring 1,500 planets without finding a single living cell, the 300 descendants of the original crew believe that “the only life in the universe is what’s inside this ship and in that thin green layer of scum covering the Earth.” Kusaka, however, won’t return home. Obsessed with the gambler’s conviction that victory is close at hand, he is determined to take the deteriorating ship through the Dark--a journey of a thousand generations--to another arm of the galaxy.

Sparrow is a 17-year-old “tech assistant” with amnesia--he remembers nothing prior to a near-fatal accident during a planetary exploration--but somehow he is the key to a mutiny that may have been going on for generations . . . and someone is trying to kill him.

Robinson’s novel offers a liberal vision of Utopia: In the ship, affection is open; sex in any combination is accepted; competition is extinct; life is revered; many are incapable of violence, and there seems to be a mutation toward empathy, if not telepathy. While the Astron’s crew may be the only life in the universe, they may no longer be the kind of human life that left Earth millennia before.

Sparrow observes that “the heart . . . is a poor thing to think with.” But it is an excellent thing to write with, and Robinson has composed “The Dark Beyond the Stars” with a lot of heart. Do not miss this novel.

THEY THIRST by Robert R. McCammon (Dark Harvest: $22.95; 450 pp. , illustrations by Wendy and Charles Lang).

A welcome resurrection of an epic vampire novel, “They Thirst” covers a week in Los Angeles, a location that is as much a part of the story as are the characters. The city that values youth above all, and where “most of the major studios in Hollywood overlook a cemetery,” is the perfect setting for vampire-king Conrad Vulkan, forever 17 years old, to launch his attempted takeover of the world. Voluntarily enlisting in his army are outlaw bikers, Barrio gang members and a serial killer on the loose. It isn’t long before the vampires number in the hundreds of thousands and it is too late for humans to mount an organized defense: “When darkness fell, the dinner bell would start ringing again.” It is up to a few brave survivors--a police detective who knows of vampires from his youth in Hungary, a television comedian, a Hispanic priest, an 11-year-old horror film fan, a reporter for a “bucket of blood tabloid”--to stop the takeover by finding Vulkan’s headquarters in a Houdini-like castle in the Hollywood Hills.

The tension is strong; McCammon skillfully draws us into his fearsome novel as the odds shift in favor of the bloodcurdling terrors that stalk the streets of Los Angeles. During the daytime, the vampires keep the humans at bay by sweeping an unsparing sandstorm down from the Mojave. The spectacular climax, uniquely Californian, plays to a long-held regional fear with incredible and sensational effect.

Author of the spellbinding novel “Swan Song,” McCammon wrote “They Thirst” 10 years ago as a paperback original. Now, for the first time, it is appearing in print as a lightly illustrated hardcover from Dark Harvest, a first-class small press specializing in horror fiction. McCammon’s ability to frighten the reader with a minimum of gore and a maximum of suspense has earned him a place in the modern horror pantheon with Stephen King, Dan Simmons, Dean R. Koontz and Anne Rice. For those who like their fiction with a shot of Adrenalin, “They Thirst” is a must read.

THE RAGGED WORLD: A Novel of the Hefn on Earth by Judith Moffett (St. Martin’s Press: $18.95; 341 pp.).

The “ragged world” of the title is our world, and a troubled world it is, wracked by crises ranging from AIDS to nuclear-plant meltdowns. The humans of Judith Moffett’s imagination are perhaps luckier than the rest of us, though, for on her Earth, gnomelike humanoids called Hefn arrive in 2010 and deliver the planet from itself. With the power to back up their directive, they order Earth to immediately cease its ecosystem-altering behavior or face species-wide infertility and the eventual demise of the human race. Moffett’s stories of humans forever changed by their encounters with the Hefn, recounted in these eight interlinked short pieces, are both intimate and heart-wrenching.

One particularly empathizes with Nancy Sandford and Jenny Shepherd: Nancy is HIV-positive and has isolated herself from all social contact, friendship and love--even after an AIDS vaccine is discovered. In one moving scene, she lies bleeding from a fall and hysterically refuses help, afraid to pass on the disease to her rescuer. “Tiny Tango,” Nancy’s story, deeply affects the reader with the pain of a pariah’s loneliness.

In “Ti Whinny Moor Thoo Cums at Last,” Jenny Shepherd is hiking on the Yorkshire moors when she is captured by a hob, a delightful gnome named Elphi who tells her of his origins as a Hefn stranded on Earth for more than 300 years and his life as a mythical creature. “In the old days, people hadn’t insisted on figuring everything out. People had accepted that the world was full of wonders and mysteries.” Like Jenny, we don’t want to forget Elphi’s story. It is a wonderful fantasy and a joy to read.

At her best, Moffett is a fine storyteller with a style and grace reminiscent of the great Theodore Sturgeon. She gives so much life to her characters that we are sorry to see them go, even though we can be cheered by the news that a sequel is in the works.

DRACULA UNBOUND by Brian W. Aldiss (HarperCollins: $18.95; 208 pp.).

Brian Aldiss, author of the 1973 novel “Frankenstein Unbound,” now pays homage to the other seminal Gothic of the 19th Century in “Dracula Unbound.” However, this is not a retelling of Bram Stoker’s classic, nor even a horror novel. It is, like much of Aldiss’s work, a time-travel novel, and travel it does--from the cretaceous era of the dinosaurs to Stoker’s Victorian England, to the United States in 1999, to a bleak 2599 when vampires have enslaved the remains of mankind.

Joe Bodenland, an inventor, scientist and mogul at the end of the 20th Century, is summoned to an archeological dig in Utah to examine an incredible find: a human’s coffin that appears to prove that man did walk the Earth with the dinosaurs, more than 60 million years before previously thought. The body in the coffin had been killed by a silver bullet.

Attempting to solve the mystery, Bodenland hitches a ride on a nightmarish time-travel device and finds himself at Bram Stoker’s home in England in 1896, the year before “Dracula” was published. He and Stoker set off on a fast-moving adventure to rid the world of the insidious disease of vampirism. For Bodenland, the vampires represent the death of mankind and the Sun; for Stoker, Dracula embodies the syphilis that eventually killed him.

Aldiss avoids the complications of time paradoxes by virtually ignoring them, ties up most (but not all) of the loose ends, and reveals what led to the demise of the dinosaurs. His wit sparkles in the dialogue of characters who are not, by nature, witty, as if the author couldn’t resist. Renfield, that sorry asylum inmate (borrowed from the original “Dracula”) who eats insects live, is eulogized with “Poor old bugger. Never harmed a fly.” “Dracula Unbound” is an enjoyable, moderately exciting story, well paced until its hurried and unsatisfying denouement.