Looking to the Future for Advice About Today : UNCONQUERED COUNTRIES <i> by Geoff Ryman</i> ; St. Martin’s Press $20.95, 275 pages

In these four novellas, English science-fiction writer Geoff Ryman wears his heart on his sleeve. The sleeve is of some shimmering space-age fabric, threaded with electronic sensors, but the heart is the old-fashioned, bleeding kind.

Or, to switch metaphors, science fiction serves Ryman in the same way that the “Charlie Slide” serves the space explorers in the first and most radically speculative of the stories, “A Fall of Angels.”

The Charlie Slide cancels out the vastness of space and enables people and goods to be transported instantly anywhere in the universe. Ryman’s fresh imagining of old problems helps him bridge the emotional distance we like to keep between ourselves and the world’s horrors.

It’s simply a good way to get from A to B. (Yes, Kurt Vonnegut, despite his wearier, wittier, more cynical tone, did much the same thing.)

The horror in “A Fall of Angels” is a political religion called the Regimen of Tanner Cahsway, which subjects future humans to rigid controls and a joyless conception of duty in order to save the universe from losing heat, running down, dying of entropy.

Ryman (“Was,” “The Child Garden”) conjures up ingenious, imaginary physics to explain how this works, and he outlines it with a brevity and clarity one wishes real physicists would imitate.

While colonists struggle to farm inhospitable planets, humans transformed into bodiless space probes--”angels”--dive into the hearts of waning suns to begin rejuvenating them with fresh fuel.

Two angels “fall” when they meet a flame-bodied alien who, despite the satanic symbolism, is really a spirit of love and spontaneity. They begin to suspect that the vaunted Regimen is just another example of rational overkill, of humans assuming godlike powers at the expense of what in the universe is truly divine.

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“Fan,” in contrast, adds very little to existing technology. A London teen-ager named Billie is smitten by the songs of Eamon Strafe, supposedly an Irish monk, and clings to his music as she grows up, endures dull jobs, loses her husband (whose chief attraction was an Irish accent) and raises an emotionally disturbed son.

Billie buys a computer program “imprinted” with Strafe’s personality and finds more intimacy with this than with any real person. Her discovery that the software is user-sensitive--that each fan creates her own Eamon Strafe--leads her to crash security at a concert to meet the actual rock star, if there is one.

The noteworthy thing about this story is that Ryman doesn’t condescend to Billie. She is loving, brave and determined; she deserves better than to be addicted to spurious experience by the media conglomerates that profit from it.

“O Happy Day!” is a fable about a feminist future in which heterosexual men, because of their history of violence and oppression, are being exterminated. Ryman neatly sidesteps the question of how women could seize power; he focuses on a group of young gay men who, like capos in Nazi camps, survive by unloading corpses from death trains.

This story is powerful both in its details--the divided loyalties, the prison psychology--and in its message: that violence, like love, is a contagion that can’t be killed off or fenced away.

“The Unconquered Country” is the most moving of the stories. Here Ryman finds an optimum balance between magic and realism. Houses, like great hollow elephants, are alive; machines and weapons are biologically “farmed” in the wombs of poor women, who are called “Desperate Flies”; the dead can speak to the living. On another level, this is a perfectly clear and straightforward account of the Cambodian genocide of the 1970s.

The heroine, Third Child, is even more vulnerable and admirable than Billie. The overkill that distant, incomprehensible powers unleash on her is literal.

“You did not starve, or wither,” Ryman has a sister’s ghost tell Third Child after she has been led to the edge of the killing fields and we realize that the fantasy has tricked us into getting too close not to suffer along with her. “You were loved, but you never became a soldier’s wife . . ., so you can lose no one else. You have lived the best life possible in the Land of the Faithful.”