OBSESSION By Ramsey Campbell Macmillan. 247 pp. $16.95 COLD PRINT. By Ramsey Campbell. Scream/Press. 217 pp. $17.50. (P.O. Box 8531, Santa Cruz, Cal. 95061).

FOR MY MONEY, Ramsey Campbell writes scarier horror stories than any other living author. His literate, sophisticated short stories and novels worm their way into your consciousness and lurk there, waiting to zap you at odd moments with a jolt of unrefined terror. If you think this mere reviewer hyperbole, get a copy of Campbell's latest novel, Obsession, an ingenious, beautifully crafted tale rooted in the horrors of real life.

Even when they treat standard motifs of horror fiction, Campbell's novels are refreshingly free of hackneyed imagery and plot devices. Obsession is a case in point. Superficially, this novel seems to be a variant on the deal-with-the-devil story -- a shopworn plot that has been rattling around as long as there have been horror stories. But Obsession is not a superficial book.

Campbell's wish-fulfillment nightmare begins in 1958, in the British coastal village of Seaward, with the predicaments of four teenage friends. Steve Innes is being persecuted by a sadistic English teacher. Jimmy Waters' father haunts the local betting shops, compulsively gambling away money he needs to run his cafe. Robin Laurel's mother is trying to keep secret the fact that Robin is illegitimate. And Peter Priest must contend with his grandmother. After being terrorized by thieves in her home, she moved in with Peter and his parents. But the old lady was unhinged by the break-in and now, browbeating Peter's mother back into childhood and his father into withdrawal from the family, she is making of Peter's home life a suffocating, living hell.

One hot, stormy July afternoon Peter wanders to a cliff outside Seaward and broods. "He could see no end to (his plight): it looked like the whole of his future. He shouted something, he didn't know what -- a plea or a curse -- into the storm that was sweeping toward him, jabbing at the black sea."

Later that afternoon, something answers Peter; he receives an anonymous letter that reads: "WHATEVER YOU MOST NEED I DO." He replies, and soon he and his three friends each have a chance to make a wish. They do, and their wishes are granted.

But "there was more to it than just wishing." Now, 25 years later, the four friends are still living in Seaward. Peter is a social worker, unsuccessfully trying to expiate his obsessive guilt over his grandmother's death. Steve is married, a partner in his father's shaky real estate business. Jimmy, too, is married; a policeman, he is relieved to be raising his family "away from city life and all that it threatened." And, after seven grueling years in medical school, Robin has set up a practice in her home, which she shares with her aging mother. Now, although they don't realize it, all four are beginning to pay dearly for their boons.

ROBIN'S INCREASINGLY senile harridan of a mother is one of the real horrors of Obsession. Paranoid, manipulative, and domineering, she rages at her daughter with the unerring accuracy of a parent -- she knows just where to stab her child's psyche, and just how far to twist the knife. (In the introduction to his novel The Face That Must Die, Campbell has written with excruciating candor of his own mother's descent into paranoid dementia.) Campbell's vivid vignettes of decaying parent-child relationships, loss of reputation and livelihood, the unraveling of a marriage, and death elicit real pain -- the pain of here-and-now, the pain that infuses Stephen King's darkest novel, Cujo. Campbell's plot moves like a fine Swiss watch, impelling each of his characters toward a crossroads of right and wrong, an ineluctable moment of free choice in which they will confront their true selves -- and in so doing, reveal themselves to us.

The unsparing bleakness of King's Cujo derived in part from its lack of a supernatural explanation for its uncomfortably real horrors. Unlike King, Campbell gives us a way out, leaving little doubt that there is at work in his novel a malefic supernatural power. But the supernatural element is kept off-stage, shrouded in ambiguity, and it affords little comfort. At one point, Steve Innes says to Peter: "I think the supernatural is just something people invent as an excuse for what they do or want to do themselves."

If Incarnate remains Campbell's best novel, Obsession could be his breakthrough to a wider readership. It is his best plotted and most accessible book, and his clear, beautifully cadenced prose is here free of the subjective ambiguities that have in the past alienated some readers.

In the introduction to Cold Print, Campbell says that he was made a writer by reading a book of stories by Howard Phillips Lovecraft. Indeed, Campbell's first book, published by Arkham House when he was 18, revealed a talent all but buried under the influence of Lovecraft's brilliant, neurotic horror fiction. This new, superbly illustrated retrospective of Campbell's Lovecraftian tales chronicles his emergence from the chrysalis of that influence.

THE UNDERLYING premise of Lovecraft's stories is rich with menace: the survival from prehistory of immensely powerful, malevolent alien beings whose form and substance are beyond comprehension, beings that now lurk on the fringes of awareness, awaiting a chance to annihilate man and retake the universe. But most Lovecraftian pastiches fail utterly. Clogged with conventions established in Lovecraft's stories -- shunned buildings in decaying, remote villages; arcane (imaginary) tomes of mythic lore with titles like Necronomicon and Revelations of Glaaki; a conveniently obtuse narrator -- and bloated with adjectives like "eldritch," "blasphemous" and "unspeakable," they evoke giggles rather than shivers. The earliest tales in Cold Print are pastiches, drawn from that long out- of-print Arkham House book; yet, in spite of considerable clutter and occasional attacks of adjectivitis, these journeyman's exercises have an undeniable power.

But it is the more recent stories in Cold Print that fascinate and frighten. "The Faces at Pine Dunes" and "Cold Print," for example, are mature horror stories of the first rank, devoid of Lovecraftian debris and told in Campbell's distinct voice. Finally, in "The Voice of the Beach" -- the most original, terrifying realization of Lovecraftian themes I have ever read -- Campbell solves the essential problem of how to represent the ineffable to a modern reader so as to evoke the terror and cosmic mystery of Lovecraft's best work.

In these stories and in novels like Obsession, Ramsey Campbell continues to break new ground, advancing the style and thematic content of horror fiction far beyond the work of his contemporaries. He writes of our deepest fears in a precise, clear prose that somehow manages to be beautiful and terrifying at the same time. He is a powerful, original writer, and you owe it to yourself to make his acquaintance.