Robin Cook's new novel is ostensibly about important, provocative issues: abortion, fetology -- experimental research with aborted fetuses -- and the influence of Big Business on the practice of medicine. But don't you believe it. Cook's fifth exercise in medical paranoia is actually about none of these things.

"Mindbend" is about Adam Schonberg, a third-year student at a New York City medical center, and his 23-year-old, accidentally pregnant wife, Jennifer. The Schonbergs are already $20,000 in debt, and their situation is unlikely to improve when Jennifer quits her job as a member of the Jason Conrad Dancers. Adam is too proud to accept help from Jennifer's well-heeled parents, and he has been "essentially disinherited" from his father, a renowned department head at the FDA.

Cook tells us early on that Adam loves his wife, but you wouldn't know it from his behavior.

" 'You told me not to worry about babies,' snapped Adam, ignoring her tears. 'You said that was your department. You did a great job!' "

Rather than let Jennifer work, Adam takes a job with Arolen Pharmaceuticals, a New Jersey-based drug firm, and plunges into the world of corporate medicine. Soon thereafter, he stumbles onto a vast, incredible conspiracy to gain control of "the entire medical profession":

MTIC, the investment group that owns Arolen, regularly sponsors Conference Cruises -- medical seminars on a luxury liner in the Caribbean. Obstetricians and gynecologists who go on these cruises return "changed somehow." They seem "strangely mechanical"; their voices are "peculiarly inflectionless," their faces "slack"; and they don't blink.

Many of these zombies jettison their lucrative private practices to join the Julian Clinic, a ritzy health maintenance organization that seems to have a predilection for abortions. They are subject to blackouts, and sometimes run amok, killing themselves and others. And here's the rub: Cook would have us believe that this has been going on for five years without anyone, except Adam, catching on.

Admittedly, the premises of most medical thrillers are pretty silly. These novels succeed or fail on their ability to tap our latent paranoia about the medical profession, with its pervasive jargon, arcane rituals, insensitive high priests and mystical medications in human-proof bottles. A successful medical thriller must be awash in detail about the alien world of doctors, hospitals and medical research centers; it must have at least one sympathetic character we can identify with; and it must have a plot that is so tight that we never stop to think about its patently ludicrous premise.

It's not as though this kind of thing can't be done well: in novels such as Cook's first bestseller, "Coma" (1977), Charles Veeley's "Night Whispers (1980), and William Patrick's "Spirals" (1983), writers have created taut, gripping paranoid thrillers.

In Cook's earlier "Fever" (1982), for example, the predicament of medical researcher Charles Martel, whose daughter has contracted an incurable cancer, is so horrible that we're willing to overlook his shrill, unsympathetic personality. And when Cook's plot begins to unravel into absurdity, he lays on so much fascinating detail about cancer and those who fight it that we're willing to go along for the ride. "Fever" is a manipulative, unpleasant book -- Cook drags us through the torments of a 12-year-old girl who has acute myeloblastic leukemia -- but at least it's compelling. Not so "Mindbend."

Much of "Mindbend" takes place outside the medical milieu Cook knows so well, so it has less medical lore than his earlier novels. It is saddled with a protagonist who is an abusive, childish bully and a plot that is dull and predictable -- you know from the way Cook has stacked the deck against the Schonbergs that eventually Jennifer will wind up at the Julian Clinic for an abortion, which Adam will try to stop. With none of the usual strengths of the genre to distract us, "Mindbend" leaves our minds free to ruminate on its underlying premise. And that premise is just too preposterous to sustain a 364-page novel.

In his afterword, Cook proclaims that his purpose in writing "Mindbend" was to "focus public attention" on "the intrusion of business into medicine." The pernicious influence of corporate medicine is indeed an important and timely subject -- one that has been explored in nonfiction books such as Stanley Wohl's "The Medical Industrial Complex" (1984). But Cook retreats from this issue, as he does from fetology and the morality of abortion, submerging all beneath his anemic plot. By focusing on ersatz suspense and its loathsome protagonist, "Mindbend" fails both as thriller and as polemic. This book is a major disappointment from a writer who has shown himself capable of better.