Mentally ill half his life, Bert Yancey, 42, is playing professional golf again. Off the tour a full five years, Yancey plays Thursday in the Atlanta Golf Classic, a tournament he won in 1969. "This is no comeback," he said today. "Comebacks are what I've done off the golf course. This is nothing but pure fun. This is a vacation. I absolutely love it."

Yancey's manic-depressive illness is controlled, he says, by the substance lithium, which levels out the steep mood swings that produce bizarre behavior. Still, his mother and brother didn't want Yancey back on tour. "The people closest to me fear the most for a reoccurence of my episodes," said Yancey, who now teaches golf at Hilton Head, S.C.

This morning was dazzling, the sun a flame dancing off the crystal droplets left on the fairway grass by a night's rain. Yancey walked smoothly, gliding as always, ever the smooth classicist who once moved with the game's giants. This was different, though. This was Bert Yancey, After.

"My mother and brother tried to talk me out of playing here," Yancey said. "They said, 'Why do you want to do it? You're doing well. You've got a good job teaching at the club. Why go to Atlanta among those wolves? Why go where they're killing babies? Why do it?'"

Yancey answers quickly. "Because I'm a golfer. Because I'm normal. Because a lot of people need to know you can have mental illness and still be a normal person doing your job. I have a responsibility now. Do you know how many kids in this country have manic-depressive illness? By being visible with my teaching and by playing four or five events on tour, I'm saying to those kids -- and everyone with manic-depressive illness -- 'I've got it, too, but I'm shaking it as long as I stay on my medicine.'"

This was Bert Yancey, Before: He won seven PGA tournaments and $688,124. Three times he almost won the Masters, and he led the U.S. Open going into the last day. If you knew golf, you put Yancey in with Nicklaus and Miller, Trevino and Watson.

But no one knew of Yancey's demons. Not even Yancey knew why he behaved strangely. He didn't know until three years ago when a doctor diagnosed his manic-depressive illness. Before the lithium, Yancey's life was a nightmare.

In 1974, then among the best players in the world, Yancey believed he was a messiah chosen by God to deliver the world from evil, to wipe out radical prejudice and find a cure for cancer. The assignment thrilled him and he did his best to complete it.

He climbed a painter's ladder at La Guardia Airport, shouting, "All right, all the whites over here, all the blacks over there." He dared the singing group, The Temptations, to a karate fight because he saw the name as a signal of the devil at work. From here in 1976, he called the tour commissioner, his friend Deane Beman, and said the Mafia was chasing him. He heard a voice once and followed its orders; searchers found him walking through the Everglades.

He washed out of West Point. A nervous breakdown, they called it. These words speak of Yancey's life after that: "Fog," a nickname based on his detachment; obsession, for the set of mind that moved him to build clay models of Augusta's greens so he truly could "feel" them; paranoia, straitjacket and padded cell; 11 hospitals and bed restraint with chains; a divorce; arrest and jail. Inevitably he also lost his golf swing, partly as a result of hand tremors that are a side effect of the use of lithium.

Those tremors are gone now, Yancey says. He has adjusted to the lithium. He has confidence in himself again. Playing in local pro tournaments around Hilton Head the last 18 months, he felt flashed of the old Yancey. The tremors had destroyed his pitching and chipping game. It came back.

His putting never went away. Even at their worst, the tremors vanished when Yancey took a putter in hand.

Stutterers may sing purely; they aren't afraid to sing. Lithium's tremors gave Yancey a plausible excuse for the bad chipping. When he first opened his golf school, Yancey had an assistant demonstrate the swing. Once a virtuoso, he was afraid to take up his instrument.

"Then, after just knocking balls around the range for a year, I felt a lessening of the tremors," he said.

A tiny smile of confession came with this: "Anyway, anybody shakes when they're scared. And I'd been scared of a lot of things for a long time."

The putting -- the putting that made Yancey a wonderful player -- was his forever.

"It kept my heart beating," he said. "I knew if I ever started hitting the ball right again, I could still play."

Those local tournaments convinced Yancey to try the tour again. Only a sprained ankle in December kept him out of the spring PGA tournament at Hilton Head. Yancey came here because, as a former champion, he needed no further qualifying.

In practice Monday, Yancey shot 70, two under par. Emboldened, he lost $90 to Raymond Floyd the next day. "I was fired up," Yancey said, chuckling, "and Ray banged me back down."

In 1976, out of a padded cell, Yancey had no job. He didn't think of playing the tour again; he thought of making it through the night. Now he does very well at Hilton Head, teaching his $1,000-a-week golf lessons. He also makes an occasional speech for the Mental Health Association.