Roger McGuinn: "We were just basically kids on the streets. We went from 0 to 60 in 2 seconds ... We went from being Beatles fans to hanging out with them."

Roger McGuinn was a Brill Building songwriter working the Bobby Darin beat when a new band out of England got him thinking.

"My job," the guitarist says of his days at the New York hot spot for hit-makers, "was to write songs like the ones I would hear on the radio. So the Beatles came out, and I noticed in the Beatles a lot of folk-music chord changes, which kind of set off a light bulb in my head. I started incorporating Beatle beats with folk songs down in Greenwich Village."

When he turned up at the Troubadour in L.A. playing unplugged Beatles covers on a 12-string in the spring of '64, he found a kindred spirit in Gene Clark.

"So we decided," says McGuinn, "to have a Beatles-sounding duo."

Not long after Clark's friend David Crosby muscled his way in, that Beatles-sounding duo grew into the five-piece Rickenbacker-toting Byrds, who ushered in the jingle-jangle morning of the folk-rock era with their plugged-in reinvention of Bob Dylan's "Mr. Tambourine Man." Fueled by Dylan's psychedelic whimsy, the ethereal blend of their voices and that opening lick -- the greatest 12-string Rickenbacker advertisement ever -- "Mr Tambourine Man" took the Byrds to No. 1 in June 1965. They returned to No. 1 before the year was out with yet another folk-rock classic, "Turn! Turn! Turn! (To Everything There Is a Season)."

Looking back four decades later, as the four-CD "There Is a Season" box set (Legacy label release includes bonus DVD, $54.98) retraces the Byrds' evolution from chiming Beatlemaniacs to raga-rocking revolutionaries and beyond, McGuinn recalls the thrill of that initial burst of energy. The box set is available beginning Tuesday.

"We were just basically kids on the streets," he says. "We went from 0 to 60 in 2 seconds. I mean, it was just overwhelming and wild. We went from being Beatles fans to hanging out with them. It was the most amazing thing. Dylan would bring Allen Ginsberg around to my house."

And soon enough, they'd gone from fans to inspirations.

As McGuinn recalls his first exposure to the "Rubber Soul" track "If I Needed Someone," "Derek Taylor came to my house with a tape George Harrison had given him in London. And he said George wanted me to know that he had written this whole song based on a riff I had done in the Byrds, 'The Bells of Rhymney.' "

Rather than repeat themselves, the Byrds moved on in 1966 with "Eight Miles High," an unintentionally psychedelic mind-rush laid to tape in Clark's last session with the band.

"It's funny," says McGuinn. "They labeled that one psychedelic, but it was just meant to be straight jazz. There wasn't really any intention of anything drug-related. That was more in the eye of the beholder. It had the word high in it, so people got the mental picture."

It was new technology, not drugs, that moved the Byrds in that direction.

As McGuinn explains, they'd spent a month on the road with a new invention he'd picked up on tour in London -- a cassette recorder.

"I'd dubbed John Coltrane's 'Africa/Brass' on one side and a Ravi Shankar record on the other," he recalls, "so we took the cassette recorder and strapped it on top of a Fender amp on the tour bus, fired it up on a converter, and listened to that same cassette, flipping it over and over again, for a month. So by the time we got back to the studio in L.A., we were steeped in this stuff. It was a conscious attempt to try to emulate Coltrane's saxophone on my Rickenbacker 12-string."

He'd have pushed the concept even further on subsequent records, but the other guys weren't interested, and by the time they got to "Sweethearts of the Rodeo" in 1968, the Byrds had settled into country-rock.

A lot of people look to "Sweethearts," recorded with session musicians in Nashville, as a groundbreaking moment in pop music history and further proof that Gram Parsons, who'd joined after Crosby was fired and drummer Michael Clarke walked out, was some kind of country-rock harbinger. To McGuinn's ears, they'd already done the country-rock thing on their second album, "Turn! Turn! Turn!," with a cover of "Satisfied Mind," and got in even deeper on "Younger Than Yesterday."

"To me, country music was just an extension of folk," he says. "So I didn't really see what the big deal was. It didn't seem like we were breaking any new ground."

A year after making their final Top 40 appearance with another Dylan cover, "My Back Pages," "Sweethearts" found them adding two more Dylan classics to their repertoire.

"He was the absolute Shakespeare of rock 'n' roll," McGuinn says. "And we were a folk-based band and he was coming out of that tradition. But he broke the mold."

For all the critical acclaim it gets in hindsight, "Sweethearts" was, on its release, a miserable failure. And before the year was out, they'd lost another founding member when Chris Hillman, who'd always pushed the country angle, joined Parsons' new project, the Flying Burrito Brothers.

But McGuinn would not go quietly, scraping another new lineup together, this time featuring a red-hot bluegrass picker, Clarence White, who'd played on some earlier sessions. It took a failed reunion effort by the original lineup in '73 to put him off the Byrds for good, going solo at last.

"I decided to hang it up," he says, "Bands on the road, it gets old. There's that initial camaraderie, which is nice, but it wears off and then you're stuck. It's like being married to three or four people you don't like that much."