The Invisible Class : GOOD HAIR.<i> By Benilde Little (Simon & Schuster: $22, 237 pp.)</i>

Benilde Little, in her first novel, “Good Hair,” has written what some might consider an oxymoron: a black comedy of manners. Contrary to what’s normally seen of black Americans in the mainstream media, where crack and guns are endemic, the only things that come out blazing here are diamond engagement rings--inherited whoppers, at that. And the cracks are hairline, in beloved Limoges passed down through generations.

The economically secure characters in Little’s engaging story are, in short, the demographic Sasquatch of America, the social equivalent of the Loch Ness monster: A few people claim to have seen them, but most reasonable individuals dismiss such talk out of hand. (“Black investment bankers, handling millions of dollars each day? Gedouddahere!”)

Most people--and certainly most nonblack people--don’t seem to know that for black Americans, “middle-class” is a term with very elastic boundaries. People with absolutely no money but impeccable home training and mores are middle-class. So are people with a comfortable income and physically middle-class circumstances (what some demographers actually calls middle-middle class). And there are people with generations-old money, folks whose ancestors were university-educated before the turn of the century--who to the naked eye would be upper-class if they were white--and they, too, are part of the black middle-class. The stratification of the middle class moves, shifts and melds every generation or so but has rarely been chronicled or discussed by those outside the race.

Little has taken the plunge, and the reader will soon find himself swimming through waters rarely charted by people unwilling to share the map with outsiders. Little’s heroine, Alice Andrews, is an intelligent, elegant girl from a working-class Newark neighborhood who feels her old life has grown too small for her (as a reporter touring a local jail, she once bumped into her best childhood friend; they were on different sides of the lockup) but wonders whether the new life she thinks she wants might merely be a better-class prison. A regular on the New York buppie circuit, Alice has recently recovered from a two-year relationship with an up-from-the-projects investment banker named Miles, who is wealthy, ambitious and terminally commitment-shy. Serendipitously, she meets a handsome, personable black man when she is upgraded to first class on return from a visit to her best friend in Atlanta.

Not only is he handsome and single, Alice’s seat mate is interested in her. This pleases her because she knows from experience that many of his peers’ inclinations lie elsewhere: “Upper-class black men, the kind I figured him to be based on his perfect teeth, conservative watch--Baume & Mercier or Cartier--and tight diction, went wild for black women with racial backgrounds that were at half-mast . . . women who look more ‘other’ than black. . . .” Turns out Alice’s assessment of Jack Russworm is fairly correct: He is a surgeon from a family of doctors. A product of several proud generations of the Boston Negristocracy, Jack went to Harvard (as expected) and on to Howard for medical school. He summers on the Vineyard, socializes with the same tautly interlocking circles of accomplished, acquisitive black professionals on the Boston-New York-Philadelphia-D.C. circuit and is expected to choose a mate from among the members of his tribe: women whose families his family knows, who are well-spoken, well-educated, well-dressed, pale in hue and possessors of “great hair--which meant long, but requiring little artificial maintenance.”

How Alice comes to terms with her complicated family history, her love for Jack and her revulsion at the incestuousness of the self-selecting black upper-middle-class makes for an absorbing read. Little, a former editor at Essence and People magazines, spares no one the sting of her tart observations. Not the smug, butter-colored girls who expect to--and who do--”marry well,” sometimes to accomplished men whose lesser social backgrounds are ameliorated but never mitigated by their awesome professional achievement. Not her white editors at the Newark newspaper she has come to loathe, who blithely assume that black always equals ghetto and ghetto always equals pathology. Not the editor on her new job who hires her--but only after breezily requesting six times as many references as she does for any potential white employee. Not even her beloved Jack, of whom she writes: “Well, it just seems like your world is a little small, that everybody you know has a similar background, one like yours. . . . Take a look at your photo album. I’m the brownest woman you’ve ever dated.”

It is, as some people have been known to wryly remark, a small, colored world indeed. If you don’t know it from the inside out, consider “Good Hair” a guidebook. The people responsible for crafting the image of black Americans much of the world sees--primarily filmmakers and publishers of various stripes--might keep copies of Little’s book on their desks as counterbalance to the dreck they keep releasing because it reflects “real” black life.