One mystery may be more totally inexplicable than any other in all of American sports: How does the PGA Tour exist?

It shouldn't, you know.

Why?

Because it is based entirely upon local civic volunteers.

The current Kemper Open at Congressional required the work of 1,282 volunteers. Hundreds are doctors, lawyers, business persons and teachers, and two are presidents of banks. The majority are in the prime of their careers, between ages 40 and 60. Fewer than half are Congressional Country Club members.

The breakdown: 752 men, 352 women, 178 juniors.

If you had to buy their time -- and these folks are, by and large, the high-priced spread -- it would cost, at an absolute minimum, more than $1.25 million, according to Kemper General Chairman Tom Ryan. A more likely figure would be close to $2 million.

The entire Kemper purse is only $500,000, and $135,000 in tournament revenue goes to charity.

"If it weren't for the volunteers, this tour would go belly up in a day," said a veteran PGA Tour official. "And, you know what, I can't figure out for the life of me why they do it."

Neither can Ryan, and he volunteered nine months of his time "14 hours a day, seven days a week" to run the event. Ryan owns a consulting company that, among other things, does architectural drawings on computers. It's high tech and high finance, but he has been getting up at 4:30 a.m. for weeks as the Kemper crunch approached.

"I've never been able to understand it, but it's great to be a part of," said Ryan, who has been volunteering for seven years. "I've seen wealthy businessmen who'll give each other a gentle bump to get in position to be the one to lift Bobby Clampett's clubs into his car . . .

"We've got a bank president who's one of the 387 marshals who control crowds on the course. He works the crosswalk at the 17th hole. Our other bank president sits back in a trailer the whole week and sells tickets or cashes checks for players. He never sees a shot. In fact, most of the volunteers never see the tournament at all."

Ryan's head swims when he thinks of people like Betty Kirkpatrick, one of the dozen volunteers who basically work year-round. She selects the volunteers' uniforms (red shirt, white pants or skirt, white hat), then she oversees their purchase (at the tournament sponsor's expense), then she gets everybody's size and distributes them. Then she fields everybody's guff if they don't fit.

When that's done, she just moves over to the transportation committee and supervises those 100 rented Cadillacs that chauffeur players and officials all over the metropolitan area. "She's here 6 a.m. to Lord knows when week after week," said Ryan. "I don't know when she sees her husband or family."

If it's not a dentist giving players towels in the locker room, it's a brain surgeon holding up a "Quiet Please" sign as someone putts. They're everywhere, from parking lots to concession stands to scoreboards.

Of his 54 committee chairmen, Ryan said, "Oh, they work from 7 a.m. to 7 p.m. for the seven days of the tournament. They usually take a week of their own vacation to do it. That doesn't count all their time before the tournament."

Thinking of these high-priced executives working 80- or 90-hour weeks for free, Ryan said, "They wouldn't do that in their own jobs. And here they have to make their own coffee."

So, how are these 1,200 people tortured, begged and wheedled into performing these superhuman and thankless tasks -- standing in 90-degree sun all day or working in stuffy trailers or coming back the day after the tournament to pick up trash and tear down the whole circus tent playground?

Does Craig Stadler stay at their house? Do the players know them by name or treat them with particular courtesy? Is there some hidden payoff?

No, no, 1,200 times no. Perhaps only 20 players stay at private homes. Players try to be nice, but that's about it. There's no secret hook.

"But there are people waiting in line to take over for anyone who steps down," said Ryan.

And that's the way it is at every stop on the PGA Tour. Folks stand in line to work for nothing, to pick up trash, to be insulted by fans who don't want to be quiet or stay in the crosswalk. The tour is full of tales of people coming from three or four states away just to be volunteers. It ought to make Ronald Reagan bust a button.

"I think they want to be a part of the game . . . Participants, not just spectators. And it's a social thing," said Ryan. "Also, there's a lot of satisfaction in pulling it off. This year, we're blowing the top off in attendance [up 20 percent over last year's best ever]. It looks like the best tournament ever, so far.

"I think people feel rewarded by being part of a unified effort. I see club members who don't even get along with each other most of the time work hand-in-hand when it comes to putting on the tournament.

"I can't be convinced that some guy works at Gate No. 2 parking cars or sits in that hot scoring trailer because he wants to look at a celebrity. That's not it.

"All I know," said Ryan, "is that although it mystifies me, it makes me feel better about human nature. I don't know why they do it, but I'm damn proud of them for it."

Sociologists love to point out that one of the great casualties of modern life is the loss of a sense of community and of group commitment to common goals. The spirit of the house-raising or the small-town fire-bucket brigade is hard to squash and, perhaps, finds ways to reassert itself.

At almost every golf tournament, the winner is given a huge trophy. His first words are usually, "I would like to thank all of the volunteers."

Now you know why they say it. And why they better keep on saying it.