The photographer Lane Stewart needed someone to pose for all the pictures: Sidd talking with the Mets' pitching coach, Mel Stottlemyre; Sidd pitching (as always) in one work boot and one bare foot; Sidd carrying his ever-present French horn. Stewart immediately cast his pal Berton, who when not teaching art at a suburban Chicago middle school occasionally assisted him on local shoots, and who bore an eerie resemblance to Plimpton's imagined Finch: tall, shyly awkward, with feet and ears a few sizes too big.

Stewart recalled the conversation with Berton:

"Joe, the Mets have this pitcher down in Florida I have to go shoot," Stewart said. "He plays the French horn, his only possessions are a rug and food bowl, and he pitches in one work boot. And he's got this 168-mile-an-hour fastball. Can you come with me?"

"Great!" Berton said.

"There's only one catch -- you're going to be him."

"Huh?"

Selected Mets officials were among the few people (including Sports Illustrated editors) even slightly aware of what the magazine was up to. They issued Berton a uniform and allowed him full access to their spring training complex, even letting him sit in the bullpen during exhibition games as Stewart clicked away. Fans would ask the weird-looking guy in the No. 21 jersey if he was trying out for the club, and he would reply: "Yeah. You'll hear about it later."

Did they ever. When Sports Illustrated hit the newsstands several days before the April 1 cover date, "The Curious Case of Sidd Finch" staggered baseball and beyond. Two major league general managers called the new commissioner, Peter Ueberroth, to ask how Finch's opponents could even stand at the plate safely against a fastball like that. The sports editor of one New York newspaper berated the Mets' public relations man, Jay Horwitz, for giving Sports Illustrated the scoop. The St. Petersburg Times sent a reporter to find Finch, and a radio talk-show host proclaimed he had actually spotted the phenom -- who, truth be told, was back in Oak Park teaching art at Hawthorne Junior High.

Alas, the enchanting details of Plimpton's story were also its downfall. Harvard and Tibet and the French horn and the 168-m.p.h. heater -- people were gradually brought back to earth by more skeptical acquaintances. (For his part, Plimpton always loved how the seventh definition of "finch" in his Oxford English Dictionary was "small lie.") As word spread over several days that the first letters of the article's secondary headline read, "Happy April Fools'," the jig was up.

Berton became a star. Television crews from across the nation went to his home and school to interview him, to have him wear the boot and throw. He became Sidd Finch to thousands of fans and was recognized wherever he went. Even in England a few months later, a man almost spilled his drink at the sight of him in an Oxford pub.

"You're Sidd Finch!" he said. "You're in Oxford!"

Soon after the hoax was revealed, the Mets decided to stage Sidd Finch Retirement Day. Berton told an oddly dejected crowd, "The perfect pitch, once a thing of harmony, is now an instrument of chaos and cruelty." He received a standing ovation as he walked down the foul line for the last time.