The Race : Ego-bound researchers compete for a cure for cancer : THE MAGIC BULLET <i> By Harry Stein (Delacorte Press: $22.95; 368 pp.) </i>

Harry Stein used to write the Ethics column for Esquire magazine, and one of his columns was about the blithe cruelty of teasing. He’d taken his young son into a shop where the proprietor took one look at the kid’s mop of curls and pretended to think that he was a she. Everybody laughed--everybody, that is, except the little boy.

It could have been your basic curmudgeonly parent column (how dare you treat my child in such a way!), but Stein used the opportunity to reflect on his own misbehavior, and offer his own brother a public apology for the pain the author might have inflicted by teasing him.

That was the point at which I reached for the Kleenex. I thought, “What an absolutely decent guy.” How few of us are capable of any kind of apology, let alone one made in front of witnesses.

Now, Stein has written a medical thriller about breast cancer--or rather, about the race to find a cure for that most fickle of diseases. But he’s still preoccupied with moral issues. On the surface this is a novel about what happens when ego-bound researchers compete for the elusive answer. What gives it resonance, though, is his interest in why they do what they do and how they feel about it.

The story takes place at the American Cancer Foundation, which sounds suspiciously like the real-world National Cancer Institute at the National Institutes of Health, the federal government’s collegial research compound, where our best and brightest are supposed to be comrades in the fight against deadly disease. In Stein’s nasty little world they are like brats on a playground, each one trying to shove the other out of the way, each one capable of whatever mischief it takes to gain advantage.

Enter Dr. Daniel Logan, a wunderkind who, in an earlier era, would surely have been played by Jimmy Stewart. Logan, an earnest first-year fellow who gave up the chance to join a cushy private practice in favor of much less money and much more idealism, is just the kind of naive scientist who still believes that God rewards good work and that doctors are lower-case deities. He’s disabused of that notion before the canapes are cold at the welcoming cocktail party, when two of the country’s top breast cancer researchers go at each other like rabid pit bulls. Still, he thinks he can survive unsullied--and, once he starts looking at Compound J, he thinks he can do what no one else has done, which is to stop the disease in its deadly tracks.

But it seems that finding a cure for breast cancer is everyone’s secondary goal. Their first? To be the man who discovers it. A little sabotage slows Logan down--a mysteriously dead research animal, a troublesome patient palmed off on a colleague’s clinical trial, a rumor started--and eventually sees him and his protocol colleagues dismissed. A more senior doctor, a master of bureaucratic politics, adopts Compound J in a desperate attempt to save the life of the First Lady (and, theoretically, the rest of us). Logan is exiled to a penny ante lab where he has to pursue his breast cancer research on his own time, and his lover and colleague, Dr. Sabrina Como (as in Lake, not Perry), has to return to Italy to find a job.

Since there is little enough justice in the real world, a true story might end this way. But Stein prefers to tell stories that have a moral spine; the bad guy may have the magic bullet but he can’t figure out how to fire the gun. Logan gets everything you only get in storybooks: sweet revenge, public acclaim, a high-profile new job, the eternal gratitude of the President of the United States and the chance to see his enemies humiliated.

If that weren’t enough, he is also reunited with the exquisite Sabrina, whose annual clothing budget and IQ are both astronomical. She has everything: empathy, a formidable brain, great looks, killer clothes. She is as worldly as Dr. Logan is provincial--and so, of course, they are meant to be together. Stein is reluctant to give us many of the details of their courtship (as though decency prevents him from invading their privacy, though it doesn’t keep co-workers from mixing work and pleasure), but he does provide the requisite steamy sex scene, which is somehow funnier than it is erotic.

“The Magic Bullet” is a seductive story, as the producers who have already optioned it for a film clearly understood. An altruistic hero, a gorgeous gal with a head on her designer-clad shoulders, interestingly idiosyncratic villains who are far smarter than the average bad guy, and an outcome so devoutly to be wished that it’s hard to resist. There are some missteps along the way, particularly Logan’s discovery of a diagram of a primitive version of Compound J, when he should be on his way to the bathroom in the building where Paul Ehrlich conducted his research on syphilis. (Is this really what it’s going to come to? A cure because someone gave faulty directions?) It’s a reach, in terms of credibility, but it’s more a distraction than an obstacle.

Stein has written with great conviction about the need to do good and to persevere and he has managed to do so without once sounding preachy. He has also researched the hell out of his subject and managed--no easy feat--to sound both informed and accessible. May some Dr. Logan, somewhere, read this book and continue to strive.