Dell Shannon, the eminent mystery writer, could have written quite a thriller. She could have called it "Whatever Happened to Del Shannon?" Its readers probably would have come of age in the late '60s, so they'd be willing to curl up with a good suspense book to remember an early hit-maker whose career had, in the words of one of his own songs, "gone to pieces."

Del Shannon, the early '60s rock 'n' roller, now 42 years old and exactly half a lifetime removed from his first No. 1 hit, "Runaway," has spent the last five years picking up the pieces, puzzling over his fall from grace. Figuring that a fall is to rise from, Shannon has followed the comeback trail traveled by Gary "U.S." Bonds, Bill Medley and, just last week, Chubby Checker. After years of rejections and false renewals, the still-youthful looking singer has eased back into the spotlight, with Tom Petty playing the mentor/producer role as Bruce Springsteen had to Bonds.

"I had locked myself away a long time ago," Shannon said before last night's performance at Desperado's. "I wouldn't hang around with anybody that had any current records. I didn't feel I fit in. I don't feel that way today."

Shannon's career is illustrative of the collision course of fortune and misfortune in pop music: Some call it the "sudden fame syndrome." For Shannon, it meant starting at the top with "Runaway" in 1961 and hanging on for five years with successive hits ("Hats Off to Larry," "Little Town Flirt," "Stranger in Town," "Keep Searchin' ") that never equaled that first mark. Then again, it was a big step up and away from Battle Creek, Mich., where Shannon sold carpets by day and sang in the Hi Lo Club at night (he'd started singing in the 7th Army's "Get Up and Go" shows in Germany in the late '50s).

"I never sold any carpets," Shannon confesses. But he did pick up a replacement name (his real handle, Charles Westover, sounding a bit tame) from a Hi Lo wrestler in search of a ring name. "He chose Mark Shannon, but I told him Mark sounded like a detective." So the Del came from . . . "riding in a Cadillac for the first time. It was a DeVille . . . Del . . . Shannon." Still, he gets letters from fans saying "it thrills me to death that I like you as a singer and now you're also a mystery writer." Shannon fires off notes suggesting his fans check the author's spelling and gender.

In 1966, Shannon recorded a concept album called "The Further Adventures of Charles Westover." "Those were the days I was trying to find the real me," he shrugs. "Which was really nuts, but also the trend. Whenever I try to follow a trend, I end up lost." At the height of his career, he withdrew for two years to fight his management over control of royalties; a series of post-'66 producers (including Snuff Garrett, Leon Russell and Andrew Loog Oldham of Rolling Stones fame) couldn't find the hit groove. The confidence started wearing thin.

By 1968, Shannon had moved into production with another '60s minute-wonder, Brian Hyland ("Itsy Bitsy Teeny Weeny Yellow Polka Dot Bikini"). To get a deal for his first group, Shannon had to sign himself up as a recording artist as well as a producer. "But I didn't have to worry about my weight, and I could smoke," he says. "I thought 'I'm not an artist anymore, I'm a producer.' I was the kind of guy that if I said I couldn't do it, I'd go out and try and prove it to you."

As a result, the '70s were as filled with misses as the '60s had been with hits. Record companies buried contracts, stopped returning phone calls, went out of business. Jeff Lynne of the Electric Light Orchestra, a longtime Shannon fan, attempted a reclamation project in the mid-'70s. "He wanted me to do myself. He was trying to motivate me," Shannon recalls. "But I was more into drinking than I was into playing. I had a little problem there with the booze."

His ultimate victory over the drinking problem came in handy during Shannon's lengthy revival program under Petty, who was going through a bitter contractual battle with his record company that would eventually lead to personal bankruptcy. The 30 days of studio time that led to "Drop Down and Get Me" were spread out over three years, as Petty first withdrew from music entirely, then came back with a tremendous album that pulled him out on the road for a year-long tour.

Despite the hard times ("I do have a lot of unreleased records"), Shannon never had to worry about money. He invested his '60s bounty wisely, particularly in California real estate. A 1972 10-acre transaction netted him more than the previous decade in the music business. "And I still have the back 30," Shannon smiles. "If I had to stop working today, I think I could get through okay."

Shannon has renewed America's interest, at least for a while; in England, he never stopped being a star since being voted most popular male vocalist in 1962 and 1963.

Shannon also did the first Beatles cover in America, "From Me to You," six months before the group hit it big in America. "A lot of Americans never had hits in England because the British did covers so quickly. I was just getting even, little war games," he laughs. "That night at Albert Hall, I told John Lennon I was going to record it because it had a little falsetto in it. At first he said, 'that'll be great,' but as he went on stage he turned around and said 'Don't do that, man.' They wanted to explode here on their own. I did it anyway and it went Top 40, higher than theirs. But after 'She Loves You,' they could care less."