When Jim McGuinn, founding member and lead guitarist for the Byrds, changed his name to Roger McGuinn, a lot of folks didn't believe Jim was really Roger and Roger was really Jim.

Rather, according to rock 'n' roll folklore, Jim had fled to Rio de Janeiro for reasons unknown, while his brother Roger took over the reins of the seminal folk-rock band, which never skipped a beat in Jim's absence.All of which explains the rather tongue-in-cheek title of Roger Mcguinn's comeback album: "Back from Rio" (Arista).

The fact that McGuinn - known for his jangling 12-string Rickenbacker guitar - hasn't released an album in more than a decade has only enhanced that mystique. But now that "Jim" is back from Rio, he finds his reputation as a musical pioneer standing taller than it ever has.

His influence on modern mainstream rockers like R.E.M. and Tom Petty cannot be understated. In fact, the term "Byrdsian" or "Byrds-esque" is overused in describing a potpourri of new bands that have tapped into the chiming guitar sound that McGuinn first touched upon with '60s classics like "Mr. Tambourine Man" and "Turn, Turn, Turn."

But no one has ever quite been able to reproduce the same magic found in McGuinn's guitar or the superlative harmonies of fellow Byrds Chris Hillman, Gene Clark and David Crosby. There was something special about it, something that captured the spirit of the 1960s while charting a timeless musical course for decades to come.

In a time when the world seems on the brink of chaos, it only seems natural that McGuinn would come out of self-imposed retirement to show the world just how timeless music can be. With help from disciples Tom Petty, Elvis Costello, Dave Stewart, Timothy B. Schmit and Michael Penn, McGuinn's "Back from Rio" does just that.

"Rio" is packed with delightful folk-rock melodies, sensational harmonies (including some with Hillman and Crosby), substantive lyrics and, yes, plenty of 12-string Rickenbacker licks. It's more "Byrdsesque" than anything since, well, the Byrds.

The album fortuitously follows on the heels of the Byrds' induction into the Rock 'n' Roll Hall of Fame and the release of the excellent Byrds box-set retrospective - arguably the best retrospective since Bob Dylan's "Biograph." The collection captures the full scope of McGuinn's creativity (McGuinn was the only original Byrd to survive a rash of personnel changes until the band officially disbanded in 1973).

Three of the best tracks on "Rio" involve famous outside writers: Jules Shear's "If We Never Meet Again," the duet "King of the Hill" with devotee Tom Petty, and the new, tailor-made Elvis Costello song - "You Bowed Down."

There's also a Beatles reference on the wickedly funny "Car Phone," on which McGuinn uses the reference "He blew his mind out in a car" while referring to "Jim McGuinn" flying in from Rio. Another fine track is "Your Love Is a Goldmine," a duet with co-writer Dave Stewart (Eurythmics).

About the only thing missing from "Rio" is a cover of a Bob Dylan tune (and considering the tepid nature of Dylan's tunes lately, it would have been interesting to see how McGuinn would have interpreted them).

For 1980 rock fans unfamiliar with the monumental influence of the Byrds, "Rio" might sound more like a Tom Petty album. But that only illustrates how much Tom Petty's own nasal delivery and 12-string sound have imitated McGuinn's sound over the years, right down to the point of covering Byrds songs ("Feel a Whole Lot Better" being the latest from Petty's "Full Moon Fever.")

In fact, on the "King of the Hill" duet with Petty, the album's first single, it becomes downright impossible to tell the difference between Petty and McGuinn.

McGuinn has actually spent the past decade living in Clearwater, Fla., (not far from Petty) just kicking back. He hung up his Rickenbacker in favor of an acoustic guitar and began playing folk music again.

Said McGuinn, "Ramblin' Jack Elliot told me that one of the best times he ever had was when he and his wife bought a Land Rover and just went from one gig to another, seeing the country and enjoying themselves. So we bought a van, and I started working again, as a solo performer. I've had more fun than I ever had before in front of an audience. It's great being able to really see the people you're playing for and have that close rapport."

"Rio" doesn't quite fly eight miles high. But on the other hand, it's tremendously enjoyable. And it's a welcome reminder how delightful a 12-string Rickenbacker sounds meshed with witty lyrics and layered harmonies.

And to reverse a a classic Byrds' line, "We feel a whole lot better now you're back."