Gary was a small-time trucker with a problem. A veteran of a dozen years on the road, he had suddenly, inexplicably developed a chronic fear of driving. A series of panic attacks - blurred vision, a dry throat, accelerated heart-beat - occurred while Gary was behind the wheel, and they cost him him his job. The final indignity found Gary in the trunk of his own car, quaking in fear, while his wife drove across the Chesapeake Bay Bridge.

Gary's dread was heightened by a realization that he did not have a name for what was troubling him. Psychically disabled by his private terror, the former truck driver was trapped in his home, dismissed as shell-shocked even by his friends and family.

Mike, the owner of a small construction business in Maryland, had a similar malaise. A fear of traveling, an inability to leave his home, had cost him his business and his self-esteem. A man who had once prided himself on his independence, Mike reached bottom when he was unable to travel to his father's funeral.

Gary and Mike are phobics, two vivid examples of the more than 10 million Americans who are significantly disabled by their fears. And in both their cases, the phobias were visited upon them without warning. What happened to them coul happen to anyone.

While many of us harbor an aversion to flying, or elevators, or high places, the phobic's fear is a wide-awake nightmare - an excessive, irrational and crippling terro arriving, unbidden, in the midst of adult life.

The phobias of the notable have long made interesting historical foot-notes. Queen Elizabeth I, it is said, feared roses. Philosopher Blaise Pascal could rarely leave his home, while Albert Camus was phobic about automobiles.

Modern-day celebrities like Maureen Stapleton, Gene Shaltt and Peter Sellers share phobias running the gamut from airplanes to heights to, in Sellers' case, the color purple. Ironically, the founder of paychoanalysis himself, Sigmund Freud, feared traveling.

Until recently, most phobics were unable to identify their problem. Through a television program they saw on phobias, Gary and Mike (not their real names) sought out Dr. Robert L. DuPont and the Washington area's first phobia clinic.

At one time, DuPont, a Chevy Chase psychiatrist whose background includes five years as director of the National Institute on Drug Abuse, might have treated his patients with traditional psychiatric methods - the familiar lie-down-and-tell-me-about-your-childhood analysis.

Three years ago DuPont had a patient who numbered among her problems an inordinate fear of driving. She presented DuPont with an outline of the work of Dr. Manuel Zane, a psychoanalyst operating a phobia clinic near New York City.

Zane's phobia program, set up six years ago, is based on a concept called "contextual therapy." Simply stated, the therapy attempts to deal with a patient's phobia in real-life situations, as opposed to more passive, analytic treatments.

This technique flies in the face of established psychiatric ideas and procedures. The "displaced fear," the belief that fears and anxieties are rooted in a deeper, subliminal fear, has long been the linchpin of traditional psychiatry.

"Before I went to see Dr. Zane in the summer of 1977, I thought of contextual therapy as a fad," says DuPont. "Obviously, I came away impressed." So impressed that last March he began his own phobia clinic in Washington. P-A-N-I-C

The phobic group that meets on Monday evenings in DuPont's office is widely varied in background. The 10 week program, which includes an evaluation session, weekly group meetings and private sessions with a contextual therapist, costs approximately $500, with an option to continue for an additional 10 weeks. Most of the Monday night grouph ave piled up enormous psychiatric bills in the past.

For the patients who were on hand at a recent meeting - five women and four men - the phobias are a laundry list of anxieties: fear of public places, of travel, fear of contamination or enclosed areas.

"A phobia," says DuPont, "is a fear of a fear, a fear of losing control. Phobias are not unitary; usually any number of symptoms are present." His Monday group bears that out. Each patient seems to harbor traces of agoraphobia, a generalized fear of the world around them. Each shares poet Sylvia Plath's contention that it is panic that runs the world - "dog-face, devil-face, hog-face, whore-face, panic in capital letters with no face at all."

Peter is an architect, a dapper-looking man in his early 30s. His fear of tunnels and crowded rooms had cost him at least one job and a half-dozen years of quiet agony.

"I had this thing about tunnels that the program is helping me with," says Peter, "but after the tunnel phobia developed, I seemed to add new fears all the times."

Peters spent years in one doctor's office or another, most recently in the care of a virginia psychiatrist who kept him on a steady diet of anti-depressants.

"A lot of these young doctors seem to be into pills as a means of handling anxiety," says Peter. "You should see the top of my refrigerator. I've got one bottle of every antidepressant known to man up there, and all they ever gave me was a skin condition."

Rebecca, a small nervous woman with a serious contamination phobia agrees. "Before I came here" she whispers "I was seeing one doctor simply for treatment of the side effects I got from another doctor's prescriptions."

Nancy, an agoraphobic housewife who had not left her home in more than six years, is another patient with a history of psychiatric failure. Many phobias seemed to be induced by physical or psychological traumas, and Nancy links hers to three major operations she endured in the last few years.

"I told people I couldn't go out because I wasn't feeling well, or had a headache, or whatever," says Nancy. "Everyone got kind of used to it, I supposed, and went along with me. Until I saw a '60 Minutes' show on phobias last winter, I just didn't know what was wrong with me."

The vital element in any phobia program is the so-called helper, a contextual therapist (often a former phobic) who guides the individual patient through the program's "practice sessions." On this Monday, Nancy and therapist Jerilyn Ross and considerable reason to be pleased. Nancy had driven to the group meeting alone, without a family member.

Ross, a graduate of the New School for Social Research (and the phobia program at New York's Roosevelt Hospital), has been DuPont's contextual therapist since the clinic began. Assisting DuPont at the weekly meetings, and working one-on-one with phobics for an hour each week, Ross confronts her patients phobias in real-life situations. Gary's "Graduation"

In Gary's case, Ross, a former acrophobic, began by riding in a car with him and slowly, over a 20-week period, she had him take increasingly difficult steps.

"One of the techniques we use with a fear of driving," says Ross, "is to move the patient along until he can drive short distances alone, with the therapist following him in another car."

Other tasks for Gary included a solo walk across the Calvert Street bridge - something he had been unable to contemplate before the program. Finally, after many weeks of practice sessions and group encounters with the other phobics, Gary "graduated." He drove alone across the Chesspeake Bay Bridge.

"What triggers the fear is irrelevant to our therapy," says Ross. "The phobias are all unique, but the physical reactions, the panic attacks, the tricks phobics use to avoid their problems are much the same. That's what makes the individual sessions and the groups work. In many cases, they thought they were crazy, that on one else had similar fears. We can show them that's not true."

Geoff is a law school dropout, a 28-year-old who began having panic attacks a few year ago. "The panic attack is so severe," says Ross, "so much like heart attack, that a second fear takes over, the 'what-if-I-get-it-again?' fear. That's what paralyzes the phobic. We try and help the patient avoid thinking about the past and worrying about the future.

"It's a matter of helping them live in the present, of making their environment their reality."

Before his panic attacks set in, Geogf was fraternity type, a high school class president, the garden variety college student. Now, despite two years of psychotherapy and a small mountain of anti-depressants, Geoff is struggling, helping out in a law office and combating what he calls his "free-floating anxiety."

Geoff has any number of theories why he became agoraphobic, tracing them to his ambition, his chemical makeup and the fact he believes his mother was agoraphobic.

"My mother was kind of lucky," says Geoff, "in that she had a psychiatrist who would take her out of the office and into tall buildings or elevators. That's what is good for me here. Going out with Jerilyn and getting off Lithlum have helped me most of all." Cryptic Messages

DuPont and Ross are careful to point out that while the phobia porogram can help any degree of anxiety, it is not for those who merely come up with sweaty palms while boarding an airplane.

"Our phobics," says DuPont, "are dealing with problems that are disruptive to their lives. A lot of people have low-level fears, but the phobics in our program spend the better part of their time and energy struggling with their fear."

For nearly 30 years, Theresa's reality had been a chronic fear of contamination, of germs and plumbing in particular. Years of psychiatric care costing a small fortune had given Theresa perfodic relief but no help in dealing with her phobia on a day-to-day basis.

"The othe day," says Theresa, "Jerilyn took me into a bookstore. It wasn't very crowded, but I began to get a level." (Phobics are encouraged to scale their fears in the phobic situation from 1 to 10. Thus, in conversation, "level" becomes a chartable experience.)

Once inside the store, Theresa's anxiety increased from a three to a six or seven. "I was doing pretty well," says Theresa, "when Jerilyn spotted a picture book on plumbing. She told me to go over and look at the book, and at first, it was awful, but once I'd done it for a bit, my level went back down."

"You know," says Ross with an engaging grin, "my answering service at home must think I'm pretty strange. I go home and find messages saying 'I went to the bridge game and it was fun,' or 'I drive four exits on the beltway.' I know what they mean, and how much they mean to the patients. I really feel like I'm saving lives." Withering Anxiety

The psychiatric votes have not been counted, and the long-term benefits of contextual therapy cannot yet be gauged. Spokesmen for the American Psychiatric Association will say only that many differenty types of therapy are in use, and that no position is likely to be taken on the merits of contextual therapy.

"When we talk about a cure," says Robert DuPont, "we're not talking about the elimination of fear, but rather the living of a relatively normal life. Our patients will have anxiety, but hopefully we can show them how to deal with it in ways that will make it wither away. In terms of improvement, virtually all our patients who have stayed with the program have made great strides."

And, DuPont believes, most anyone can be helped by the phobia clinic.

"When I started with the phobia program," says DuPont, "I used to get pretty worked up if I got stuck in traffic, and tried to schedule myself so that would never happen. Finally, I started timing myself in traffic jams, and found that I really wasn't losing much time - just 10 minutes or so, though it seemed like half an hour. Sometimes, you know, just staying in the doctor's office won't do the job." CAPTION: Picture, Psychiatrist Robert L. DuPont, founder of Washington's first phobia clinic, and phobia therapist Jerilyn Ross. By Margaret Thomas - The Washington Post; Illustration, "All right, I am afraid! I'm afraid to eat, to drink, to smoke, to drive, to fly, to breathe! And why shouldn't I be?" Drawing by Alan Lunn; Copyright (c) 1962 The New Yorker Magazine Inc.