Insights and Aliens : THE WALL OF THE SKY, THE WALL OF THE EYE.<i> By Jonathan Lethem (Harcourt Brace: $23, 294 pp.)</i>

Once, there was no genre fiction, just stories. When Homer injected gods and goddesses into ancient news events like the fall of Troy, nobody asked if it was fantasy, historical fiction or even poetry. He was just a storyteller. Today, writers who fail to fit into a category, or who straddle several genres, don’t always get the recognition they deserve.

One such boundary-hopper worthy of wider readership is Jonathan Lethem, who mixes science fiction, social commentary, serious reflection and Disney-esque humor in the page-turning, economical style of a suspense thriller. His first novel, “Gun, With Occasional Music,” was a wisecracking yet melancholy Raymond Chandler parody set in the future with a skeptical, freethinking hero who pits himself against an autocratic state. (This earned Lethem two science fiction awards, the Crawford Award for best fantasy novel and the Locus Award for best first novel). He consolidated his reputation with the dreamy “Amnesia Moon,” a surreal, futuristic, coming-of-age road novel in which the hero grapples with memory’s slippery nature while searching for his place in a changeable world.

No “Star Wars” this, but science fiction with a meditative bent. Sure, Lethem exploits all the sci-fi stereotypes, from genetic engineering, scientific hubris and parallel universes to global disaster, mutated species and a drug-addicted populace in thrall to the state. But these plot devices are always in service to reflections about humanity, applicable to any age, in any genre. Lethem clearly owes a strong debt to Philip K. Dick, the philosophically minded master of the sci-fi genre. But he’s also not that far removed from the social and political satire of playful postmoderns like Robert Coover.

“The Wall of the Sky, The Wall of the Eye,” a collection of seven short stories, is the latest impressive distillation of Lethem’s special talents. Though set in the future, these stories also represent his closest involvement yet with present-day concerns. Certainly, there is an abundance of science fiction paraphernalia--robots, space aliens, sentient animals, time warps and a world where the boundaries of mind and body are fuzzier than they are for us.

But there are also the down-to-earth concerns of family, male-female relationships, friendship, the nature of self and self-esteem, our ability to connect with others (or not) and the wider issue of what it means to have a community--as well as explorations of such social evils as racism, crime, drug addiction and the cult of celebrity.

The connecting thread between the two worlds, the real and the fantastic, is sometimes quite tangible. Several of the stories take their inspiration from literal interpretations of platitudes. One character really does inhabit a “living hell.” The criminals in “Hardened Criminals” are exactly that, their bodies crushed and placed in a hard, transparent solution for display in a prison wall.

But it is the less discernible interminglings of the everyday with strange futurity that give Lethem’s commonplace themes their awful power and lend his best stories an epic, lyrical quality that makes them memorable. His small masterpiece, “The Happy Man,” is as chilling as anything by Edgar Allan Poe, largely because the fantasy aspect of the story accentuates the horror of an event that could happen in real life. The protagonist is Tom, who has actually died, but as the family’s only wage-earner--he has a wife in graduate school and an 11-year-old son--he is allowed by “the courts” to return. The only difference is that periodically his soul leaves his body and goes to a place he calls “Hell.” In Hell, he is always a small boy who never gets breakfast. He also fears and lusts after a beautiful witch and tangles with a sinister, jovial figure called Colonel Eagery, reminiscent of earlier malevolent father figures in Lethem’s work.

Tom resists the idea that Hell “means” anything. In fact, the story’s shocking climax makes clear that it means a great deal. Implicit is the broader point that if people examined their lives more carefully, their losses to themselves and to those they love, might not be so great. More disheartening is Lethem’s hint that Hell is a constant in all of us.

Lethem paints a bigger picture when the real and the fantastic join hands to satirize contemporary life. As always his approach is multilayered. “Vanilla Dunk” is ostensibly a satire of the sports world--a future world where basketball players can put on special suits to exhibit the skills of the great players of the past--but it’s also a meditation on the meaning of life, where winning or worldly achievement is weighed against internal honesty.

An important sub-theme has to do with racism and the enduring nature of hatred. The narrative centers on a feud between an arrogant, racist white basketball player, who wears a suit that enables him (ironically) to simulate the skills of the African American star Michael Jordan, and an angry African American player who wants only to humiliate the jerk. The white guy gets the worldly success, the African American a moment of decency. Who’s the winner?

But Lethem is not a protest writer. His philosophy is perhaps closer to that of a character in “Five F---s” who says, “Human lives exist to be experienced, or possibly endured, but not solved.” Like the dual explanations given for the toothless space alien panthers in “Light and the Sufferer,” reality, Lethem suggests, can be interpreted in different ways.

If I have a nagging doubt about Jonathan Lethem as a writer it’s only that the sci-fi devices occasionally seem artificial--that is, not organic to the story. It’s a problem I have with science fiction in general. The genre uses external mechanisms for subtly internal things. Examples from Lethem’s stories include the alien panthers who probably represent soul or conscience, and the basketball suit metaphor, which heavily drives home the lesson that we should pay attention to our own skills and instincts, not someone else’s.

He’s definitely no Jorge Luis Borges, for whom the detective story was a handy frame for intense metaphysical speculation. Yet Lethem’s storytelling power so often overcomes the mechanical aspects of his tales--I’ll never forget his description of stony faces crushed into a prison wall, faces that can still speak--it’s easy to forgive him his shortcomings. After all, even Homer had his repetitive side.