To be a patient, know your doctor.

There are several things we need to know about today's changing doctors if we want to get the most benefit when we need one.

Like those kindly Norman Rockwell doctors on those old Saturday Evening Post covers, today's doctor is still a person who first observes, then diagnoses, then treats. But he and, increasingly, she are doing so in the throes of an upheaval in the way medicine is paid for and delivered, changes in the way patients view doctors and changes in the way many doctors view patients.

If we patients understand these, we may understand doctors better, we may understand ourselves better and we may be better prepared for the good and bad in today's medical care.

For example:

Competition is getting ever keener among doctors and health plans. There is also growing concern among doctors -- read almost any medical journal -- over the loss of human contact virtually dictated by today's ever more technological medicine. Doctors, at least a great many of them, I am convinced, are therefore trying harder to be the traditional, caring doctor -- who not incidentally attracts and keeps patients.

Many doctors are doing other things to try to satisfy patients. Many are paying more attention to how patients are treated on the telephone. Some are adding evening hours.

Many are trying to give patients more information, both face to face and by brochures and cassettes -- on "how to live with diabetes" or "how to manage after a heart attack." Activities like these are being urged on doctors as "marketing" -- good business. But they also can benefit patients.

Good doctors are still busy, of course. And they are often preoccupied -- with sicker patients, with all they should know about medicine, with personal problems. Dr. Judah Folkman of Boston Children's Hospital has said: "There are things we physicians are opaque to . . . It's so hard just to take care of patients and not make mistakes every day. You know there are 25,000 diseases that have names, and you've got to pick the right one and not be wrong. So we're thinking about a thousand problems all day, and we don't think enough about the patients' anxieties."

Knowing and understanding such inevitabilities, "the patient has to take some responsibility too" for good care, Lynne Merryfield, a Washington area medical practice and marketing consultant, points out.

How? In part, by realizing that the average doctor wants to do right by us, but is also busy and liable to rush us. We can and should speak up and let the doctor know that we expect his or her full attention, and a reasonable amount of time when we need it.

With most doctors, it is possible to do this without rancor, just by saying, "I still have some important questions" or "I need a little more advice today."

Sometimes when I see my own doctor, my needs are fairly simple and I'm satisfied with a fairly brief encounter. Once in a while I try to say things like those above, and I've even said, when phoning for an appointment, "Please tell the doctor I need to talk to him some." He then may allot me an added time slot on his schedule, or at least in his own mind.

We must also ask questions, even the dumb-sounding ones.

As pressing as our questions may be, we don't always remember them in the stressful moments in an examining room. We can prepare ourselves by reviewing our questions in our minds beforehand, or even writing them down. Doctors once scoffed at the picky patient who appeared with a written list of questions. Maybe some doctors still do. Let them scoff. If that's what it takes, put your questions in writing and even hand the doctor the list.

"Today medicine has answers and people should be urged to seek them," says Dr. Sheldon Greenfield of the University of California at Los Angeles. "Patients must meet the doctor more than halfway . . . They have to tell the doctor they want to change their diet -- or why they can't spend $4 a day on medicine."

If we want good care when we're sick, we should look for a caring doctor when we're well. That isn't always easy. Traditional health insurors don't usually pay for routine physicals. They will pay, however, if you arrange an examination to investigate a complaint. And most prepaid health plans urge you to select a personal doctor and have an initial physical exam. They know that if you have your own doctor, one you can count on, you'll most likely stay with their plan.

What if you're unhappy with a doctor, or something the doctor does -- or omits? Say so. Say it before it becomes a big, festering issue. Then you may be able to say it amicably, without arousing an unproductive defense reaction.

If that doesn't work -- ever -- look for another doctor. But if you find that you're constantly changing doctors, finding no one "just right" and doctor-hopping, examine yourself. There are no perfect doctors, only other human beings who are right sometimes and wrong sometimes and whom we can help, while helping ourselves.