The lights went out in John Lewis' Costa Rica hotel room one night in 1978, an event that normally wouldn't have rattled this Philadelphia lawyer with serious eyes and a confident air. But Lewis was scared. He put down his copy of "The Decline and Fall of the Roman Empire" and quickly shoved a couch against the door. Then he waited.

He was waiting for Robert Vesco, the famous "fugitive financier" he'd been chasing for years. Vesco wouldn't actually murder him, Lewis thought in the darkness. That would be dumb. Because just that day, Vesco had told two of Lewis' associates: "I know you've got Lewis with you, and I just want you to know, to show my good faith, that I haven't had him wasted."

J. Edgar Hoover chased John Dillinger. Sheriff Pat Garrett stalked, then shot, Billy the Kid. David Janssen spent four years on ABC as "The Fugitive," searching for the one-armed man. Now John Lewis has joined the hunters, spending the last nine years on the trail of Robert Vesco.

Lewis never did see Vesco that night in Costa Rica. It was just a power failure, and in 10 minutes the lights blinked back on. But it was yet another episode in a journey that has taken Lewis from his five-bedroom Pennsylvania fieldstone to a world most people see only in paperback thrillers.

With the help of his home computer, Lewis, a partner with the Philadelphia firm of Morgan, Lewis & Bockius, has so far recovered more than $30 million in damages against a bank and a law firm that he says helped Vesco. The Securities and Exchange Commission, which contends in a court suit that Vesco looted $392 million from the empire of the Geneva-based mutual fund Investors Overseas Services, has yet to retrieve a cent.

Lewis' prey, a tall man with black hair and darting eyes, is the most famous white-collar criminal suspect of modern times. There are five federal indictments pending against him. The SEC says he owes millions of dollars to hundreds of thousands of mutual-fund shareholders all over the world. The FBI, the Justice Department and the State Department have gone to extraordinary, unsuccessful lengths to snare him. He has allegedly tried to buy the occupants of several White Houses, offering cash for a political fix to his legal problems. (The most well-known charge is an alleged $200,000 illegal campaign contribution to Richard Nixon.) He once owned a sprawling Costa Rican ranch, protected by his private police. And he used to enjoy the "Silver Phyllis," his own Boeing 707 with a discothe que, salon and galley that served pepperoni pizza, Vesco's favorite, as well as seven-course meals with accompanying wines. One biography says the jet was a flying bordello.

Lewis loves every tarnished detail. "It's something out of James Bond," he says, with joy. "There's a certain pizazz about the whole thing."

"Moderate" is more the word for Lewis, although he still subscribes to Mad magazine. He went to Princeton and Harvard Law School. He smokes a pipe, plays squash and tennis, is an occasional lay reader at his Episcopalian church and will repent with a lunch of cottage cheese after eating a pizza during the Phillies game the night before. He is 45 years old and has a lean, stern face and thick eyebrows. In his Philadelphia office, where he talked about Vesco one recent morning, are pictures of his wife, Mary Ann (Wellesley '61), and his three sons, riding horses at the same Colorado ranch where they vacation, without fail, every single year. "I'm a happy guy," he says.

Perhaps his only excess, and he is careful not to go on about it at parties, is Robert Vesco. "Fundamentally, I do not allow anything to come between me and my family," Lewis told Philadelphia Magazine. "But I must say that for most of the last nine years, my professional practice, my every waking moment, my life, in fact -- has been Vesco."

His initial mission, as the lawyer for an accountant representing a group of Canadian and European investors, was to retrieve $60 million for his clients. Of that, he got more than half. In the process, he took 100 depositions, a task that led him to England, Switzerland, Luxembourg and Costa Rica. During one trial, he and a partner holed up in New York's St. Moritz Hotel for nearly four months, preparing the case. Lewis got up at 5:30 a.m., worked until breakfast, stopped briefly and worked through the day, breaking only for squash. After dinner he worked until 2 a.m. "Each part of it was so utterly fascinating," he says, "and in some cases, thrilling."

"They ought to give him an award," says Stanley Sporkin, the chief counsel at the CIA who, as the SEC's chief investigator in 1971, pushed the Vesco case when he says nobody cared. "He's done a magnificent job. He's done things quietly, and on his own. He did it with a passion."

Lewis gets a little embarrassed by this and, anxious not to seem a grandstander, carefully says it was Morgan, Lewis who made it all possible. He specifically mentions the help of Jerry Calvert, one of his partners. In fact, there are a number of Vesco investigators and Vesco-hunting lawyers, particularly in New York, all hired to retrieve money from other mutual funds that Vesco controlled. But Neil Lang, a chief trial attorney at the SEC, says that Lewis, "in terms of litigated judgments," has "been the most successful."

Lewis, who never lost any money to Vesco, says he's never met him but would like to. He keeps a tape recorder by his office phone, just in case Vesco calls.

Has he considered that he may be obsessed? Or living vicariously through a man whose life is a heisted jewel compared to his?

Lewis thinks not. "I tend to believe that if I had the same intentions as Vesco," he says, purposefully, "I could have done a better job of it."

There is so much Robert Vesco lore in the nation's libraries and legal documents that there are now Robert Vesco buffs--Vesco included. "He apparently eats it up himself," says Lewis. "He'd really rather be the fugitive financier than the guy in the suburbs with two kids and a good job."

Already, two Vesco books have been written, which is about how long it takes to fully describe his exploits. (Lewis himself asks people whether they want the five-minute or the five-hour version.) Here's the five-minute one:

Vesco, the son of a Detroit auto worker, dropped out of high school and worked briefly as a salesman. In 1966 he formed International Controls Corp. of Fairfield, N.J., a company that made tubes and valves for NASA. By 1970 he was a millionaire. A year later, he took over Investors Overseas Services, the mutual fund conglomerate. The SEC contends in its suit that he soon began transferring the mutual-fund savings into "shell" companies that he controlled. From that, he planned to create "Vescoland," an international business zone in Costa Rica, recognized as a sovereign state with its own government, laws and stamps. But by then, the SEC--and shortly thereafter, John Lewis--were chasing him.

"Standoffish and introverted as a youth," writes Vesco biographer Robert Hutchison, "Vesco later said he felt discriminated against because his name ended in a vowel." He weighed about 200 pounds, Hutchison adds, "with a tendency toward spreading flaccidity. . . . He did not stare at people but coldly peered through them, and his speech was often brutally direct."

In recent years, Vesco's name has surfaced in official Washington. He was alleged to have tried to bribe the Carter administration to solve his legal problems, although he was not indicted. He has caused problems for the current administration as well, hiring a lawyer who, in 1972, paid former national security adviser Richard V. Allen a $10,000-per-month consulting fee. When the transaction was reported in the press in 1980, Allen briefly resigned from the Reagan campaign.

Now Vesco is believed to be living in Nicaragua and is said to be much thinner and sick, perhaps suffering from a heart or urinary-tract problem. Some say he's lost as much as 80 pounds. In May, he tried to enter Costa Rica for emergency medical treatment, but wasn't allowed to leave his plane. "I think he's looking for a safe haven," Lewis says.

Lewis' own tale is no less intricate than Vesco's. For that reason, it comes in a five-minute version, too. "There's really nothing more boring than some lawyer basically telling war stories," he says. "But I have found that the name Vesco is magic." He settles in on his couch.

In 1973, a Canadian accountant named John Orr was named by the Supreme Court of Ontario to represent the 200,000 investors who had lost $60 million from one of the largest mutual funds controlled by IOS. Lewis, after some lengthy legal preliminaries, sued Vesco and two of his top assistants, alleging fraud and theft; the Bank of New York, which Vesco had used as a depository; and Willkie Farr & Gallagher, the law firm that Lewis charged had helped Vesco with most of his IOS and Fund of Fund deals.

The court ruled against Vesco and his assistants, who are both, like Vesco, still at large.

More controversial, at least in Lewis' life, was suing the bank and the law firm. Even some of his own partners seriously questioned the propriety of going after brethren. "He took on the establishment," says Sporkin. "And he's part of the establishment."

Then the process of interviewing potential witnesses began. Lewis went to New York, Miami, Washington, Atlanta, Los Angeles, the Bahamas, Costa Rica (where the lights went out), England, Switzerland, Luxembourg and Ferney-Voltaire, France, the headquarters of Vesco's IOS. "When I was over there, I was sort of like an archeologist, in a sense," he says. "There were all these empty rooms with maps of the world on them."

On Dec. 28, 1979, he settled with the New York law firm for an undisclosed sum. Back at Morgan, Lewis, he was a hero. But there was still the Bank of New York to fight. He and his partner, Jerry Calvert, camped out in the St. Moritz, on and off, from February to June of 1980. The hotel staff even got a little excited about the case. Then on July 18, a six-woman jury found the Bank of New York liable. The damages against the bank, plus the undislosed damages from the law firm, wound up as more than $30 million.

The St. Moritz maids and bellhops brought in champagne.

In the two years since, nothing Lewis has done at the firm has lived up to the Vesco case. There was a war between Penn Central and the Hunt brothers of Texas for the control of the corporation, which Lewis, representing Penn Central, won. There was a patent case over automobile batteries, now about to go to trial. But in the back of his mind, there's always Vesco.

"Time is marching on," he says. "I just haven't made up my mind what is the best course of action. Sometimes, not doing anything in terms of spending your client's money is the best course of action. I just don't know.

"It's unfinished business with me, though, and I must say that annoys me. Everything is done now, as far as I'm concerned, other than Robert Vesco." He muses about hiring investigators to find him or, more realistically, perhaps meeting with the SEC to discuss a joint offensive.

"Yes, I do miss it," he says. "So in that sense, I'm happy it's unfinished. I'm of two minds. I want to see the Vesco thing over with, but at the same time I'm reluctant to see it all go away, because it's so fascinating. And frankly, that's one of the reasons I turned last year to writing a first novel. I've wanted something to sort of ease the letdown and of having most of this stuff behind me."

That first novel, he explains, is "sitting around" in the offices of two literary agents in New York. It's about World War III and needs, in his words, "fleshing out." So now he's started a second one, fiction, about a man named "Ralph Vicor." He bears a remarkable similarity to Robert Vesco.

Vesco, Lewis believes, is growing desperate. He thinks he may try to come back to the United States. "He's been out of the civilized world for six or seven years," reasons Lewis. "We've basically shut him down. It must get sort of boring talking to the same old cronies night after night."

And if he finally meets him?

For one thing, it'll be strictly business. "I draw the line at going out to dinner," says Lewis. He thinks about it. "He does have a great deal of surface charm, apparently," he says, mentioning a time when Vesco, meeting with lawyers, wrote the letters "LPI" on the blackboard. "And somebody said," Lewis recalls from a story he's heard, " 'Bob, what's that stand for?' And he said, 'Ah, that's my new corporation -- Looting and Plundering Inc.'

"Probably if I got to know him," Lewis continues, "I could grow to hate him. Because I despise everything he stands for. But I've never met the guy, and I don't want to overdo it and say I sit here with a dartboard with Vesco's face on it . . . But I don't think it's become an obsession with me."

Lewis, finished with his tale, is winding down now. But less than two feet away, sitting nearly unnoticed by his office phone, is his tape-recorder.

Waiting for Vesco.