Their Love Triangle Was a Double Helix : SUMMER PEOPLE <i> by Marge Piercy (Summit Books: $19.95; 419 pp.) </i>

A novel about three artists whose lives intertwine around a Cape Cod pond, “Summer People” is a chronicle of romance among ambitious bohemians, written by the poet and novelist Marge Piercy. The novel is an artless meditation on art, constructing three unconventional lives (a married couple in a decade-long bisexual triangle with a neighbor) out of all too conventional materials. Willie and Susan have been married for nigh on 30 years and been involved in a bisexual romance with their neighbor, Dinah Nathan, a composer and widow of a famous poet. But after a near-fatal accident, Susan tires of her romance with Dinah and ejects her from the family circle. Dinah finds love elsewhere, in the arms of a virtuoso flute player, and while the pair make beautiful music together, Willie and Susan’s marriage becomes increasingly strained by Susan’s infatuation with another neighbor, wealthy Tyrone Burdock, whose social blessing Susan covets. When Susan’s son Jimmy breaks an unspoken taboo by wooing Tyrone’s daughter, things fall apart, wealth asserts its prerogatives, Susan receives a tragic comeuppance, and Dinah, whose love has always been pure, is cosmically rewarded in kind.

It is a novel that yields more in summary than it does in the telling, since the structure of the tale--with its several bisexual characters and interlacing romantic triangles--has the mathematical fascination of a double-helix model. But any such interests are quickly dulled by Piercy’s plodding narrative, and what remains is a Harlequin Romance vision of Bohemia, with artists substituted for the dashing doctor or the millionaire.

In the Piercy equation, career constitutes character--and one cares about the characters in direct proportion to the size of the romantic fog enshrouding each one’s chosen field. Dinah Nathan has, in Piercy’s view, a suitably ennobling job. A composer once married to a famous poet and involved with a sculptor and then a virtuoso musician, Dinah is the implied heroine of this tale. But we don’t think much of that millionaire businessman, who lives with his ill-gotten gains across the pond, or of Susan, a mere fabric designer infatuated, to make matters worse, with the millionaire. This Gilligan’s Island crew changes partners incestuously over the course of the spring and summer season while telling each other exactly how they feel, and, astonishingly, always knowing: a testament, perhaps, to the fact that Cape Cod is a mecca for psychiatrists. Not one of “Summer People’s” characters is hostage to ineffable emotions, and their inner lives are as engrossing as grocery bills. “I love performing, but after a time I lose myself,” says the virtuoso flute player to the composer, embarking on yet another detailed dissection of that relationship. “I distract myself from my pain by helping you. You distract yourself from your pain by helping me,” says the sculptor to his latest paramour, insightfully. “I think it’s beautiful,” she responds. “I think being open to each other and helping each other is what being human is all about.”

Despite her 14 volumes of published poetry, Piercy’s writing seems to be always straining after poetic effects that do not come naturally. Her language lacks a distinctive voice and is mired in cliches: “She had come to Willie ripe but oh so young,” she writes, and “her body stirred under his casual glance like a grove of aspens in the wind.”

In between such revelations, Piercy numbs the reader with the latest developments in Cape Cod real-estate: quarrels over cesspool design, building permits and beach access rights. These things do obsess Cape dwellers, and though they provide a certain insight into small-town politics and social life, in the absence of a coherent portrait of the social forces at work in the larger town these bites of information have no place to land. Though ostensibly a novel about class conflict and small-town society, “Summer People” does not transcend the domestic dramas of its central characters; there’s very little sense of how they integrate into the community, and how, for example, a bisexual triangle would be received by those other winter townspeople who hardly rate a mention--the more conservative Portuguese shop owners and fishermen who share the off-season cape with year-round artists and whose children grow up side-by-side in school. In this sense the novel is guilty of the same oversights and condescensions of which the millionaire stands accused.

But what is most disappointing about “Summer People” is the opportunity Piercy has missed to examine the social structure of the East Coast art world in all its contradictions and hypocrisies. “Summer People” takes the easy road of pitting the “haves,” that rich, soulless businessman, against the soulful “have-nots,” those artists. How much more interesting it would have been to take on the class structure of the art world itself, the way in which anointed artists--much more than the merely wealthy--rule the Cape Cod social roost; if not in the Hyannis compound of the Kennedys, certainly in the Wellfleet-Provincetown axis where the book occurs. In the real art world, the artist showmen have become the millionaires, buy the most lavish beachfront properties, hire poor artists as their bartenders, and the nouveau riche Tyrones hope against hope to be invited in. Sadly, there isn’t room in Piercy’s imagination for soulless artists and soulful businessmen, or for the sort of contradictions in character that make human beings interesting.