We live in a science fiction world. Space travel, atomic energy, genetic engineering and high-tech entertainment were al1 once the province of yesterday's escapism.

Contemporary medical thrillers provide a good example of how times have changed: There is no clear dividing line between realism and science fiction. Medicine is advancing at such a dizzying speed that such novels cannot help but cut close to home.

Blairsville, Ga.. writer Sharon Webb is swiftly becoming an acknowledged master of the form. After the success of Pestis 18—concerning the dangers of biological warfare—she presents Half­life. This time the subjects are the brain, multiple personality disorders, psychic research, the risks of attending summer camp and the seeming oxymoron of ethics in espionage.

As with all god thrillers, the plot is complex, and a review is hard-pressed not to reveal details that will spoil the surprises.

With that in mind, a few hints about what makes the novel work can be offered. An artificially developed psychotic personality is the perfect assassin, known as "Jonathan" in the story. "Jonathan" is introduced into various characters' mind as Ms. Webb is enough of an optimist, however, to suggest that if one does not already have the potential to be a murderer, a tremendous amount cf monkeying around with the brain may still not produce a killer.

She uses an Atlanta setting effectively. Her characters are all believable. Ms. Webb may be at her best when describing people at work. A good example is when a nurse attempts to save the life of someone who has just threatened her own life, because that is what it means to be a nurse.

Some of the most suspenseful scenes involve a phrase, the trigger mechanism, being slipped in front of the unsuspecting victims of the experiment. The only weakness in maintaining the tension is that it takes all of a few seconds to figure out who the baddie must be.

Half­life is finally a book about fear—not only because of gruesome murders but primarily arising from the idea that one might be the unconscious tool of someone else's designs. The mind is the final battlefield.

Victor Koman's Solomon's Knife is a medical thriller of a different kind. Instead of Ms. Webb's blend of espionage and horror. Mr. Koman offers a courtroom drama that focuses on one of the most controversial issues of our time.

With the recent Supreme Court decision sure to rekindle the abortion debate in the 1990s, Solomon's Knife asks fascinating questions. What if one day a woman goes to the hospital to have an abortion and is asked to sign a pregnancy termination contract? Whàt if the doctor who removes the unwanted fetus, in compliance with the contract, then transplants the fetus to another woman who has desperately been trying to get pregnant but has found no viable method until now? What if technology renders abortion an obsolete technique?

Transoption is the term Mr. Koman gives to this operation. The breakthrough is based upon a method by which any woman's womb can be made hospitable to any fetus.

Mr. Koman develops the idea in high romantic style. The doctor who performs the unauthorized surgery ls Dr. Evelyn Fletcher, one cf the best realized characters this reviewer has ever seen. Condemned by some as a Frankenstein, hailed by others as a saint, she undergoes the torment that has always been the reward for medical trailblazing.

The ethical time bomb is set off after the birth of the transplanted baby. It is discovered that the child needs a bone marrow transplant from her original mother. Secrecy can no longer be maintained. The mother agrees to save the infant but is persuaded by a litigious boyfriend to sue for custody.

The most dramatic portion of the book covers the courtroom battles over Baby Renata and the accompanying protests. There is real brilliance here. Mr. Koman shows how transoption would lead to rifts and new alliances in the abortion wars.

He posits that the march of science could make possible the first pro-choice/pro-life alliance among those who will see transoption as a boon. But he does not avoid the satirical implications either: There is a second alliance of pro-choice and anti-abortion forces who oppose giving women this particular alternative, the first for political reasons, the latter for religious ones.

Before this gripping novel ends, Dr. Fletcher must put up with being called a Nazi by overheated partisans of both left and right. Mr. Koman is asking those who would defend life or choice to really think about what the words mean. It does not ruin the denouement to praise Mr. Koman for his demonstration. both intellectually and emotionally, of what it will mean to the world when there are literal co-mothers.

Solomon's Knife is a novel that does what only a great novel can do: It gives us a new context.

Brad Linaweaver is a science fiction novelist who lives in Atlanta.