“The feeling was just pals hanging out,” the photographer Henry Diltz says of the February 1969 shoot that yielded the cover of Crosby, Stills & Nash, the first album by one of the world’s first supergroups. “Those were my friends—the people I hung out with and smoked grass with.” Thanks to Diltz’s indelible photograph—three guys on a ratty couch on the porch of a little white clapboard house—that record became forever known as the “Couch Album.”

It also fixed David Crosby, Stephen Stills, and Graham Nash in the public imagination as a trio of friendly neighborhood rock gods (from the Byrds, Buffalo Springfield, and the Hollies, respectively) who had a supernatural ability to bring front-porch intimacy to stadiums and arenas and festivals—including Woodstock, where they played their second-ever live show, joined by Stills’s old Buffalo Springfield bandmate Neil Young, in front of, oh, about 400,000 people. “We were scared shitless,” Stills said of the occasion.

The story of Crosby, Stills, Nash & Young—and how Diltz captured them at work and play in his viewfinder—is now spun out in an edition of 2,000 of CSN&Y: Love the One You’re With, an appropriately epic photographic chronicle of the band, which includes recollections from Diltz, the musicians, and their associates, along with commentary from biographer Dave Zimmer.

Weighing in at 835 photographs and including facsimile pages from Diltz’s daybooks, this is a multi-decade visual saga with as many twists and turns—and as much heart-on-its-sleeve appeal—as “Suite: Judy Blue Eyes.” It’s only fitting for a band that, as Nash writes in an evocative introductory essay, was “like a bittersweet love affair, with periods of ecstasy, heartbreak, separation, reunion and joy.”

“Those were my friends—the people I hung out with and smoked grass with.”

Diltz, who turned 85 last year and is still out there shooting, first picked up a camera in a secondhand shop in 1966 while on tour with his own band, the Modern Folk Quartet. (They are perhaps best known for their 1963 Phil Spector–produced earworm, “This Could Be the Night.”) “When you’re a musician and you live in Laurel Canyon,” Diltz says, “everyone you know is a fellow musician. So I was just photographing my friends, and one by one they became famous.”

Diltz went on picking his banjo, but, more and more, his instruments of choice were Pentaxes and Nikons. His early subjects were the Laurel Canyon pantheon at its golden apex: the Byrds, Cass Elliot, the Monkees, Joni Mitchell, the Doors, et al. In 1968, Mama Cass’s Earth Mother matchmaking brought Crosby, Stills, and Nash together, with Diltz always nearby, clicking away. The trio, with its emphasis on songcraft and otherworldly harmonies, pointed the way out of an indulgent era of psychedelia, acid rock, and preening guitar gods—“King Dick kind of music,” as Nash calls it in the book. With the addition of Young, they were practically America’s own Beatles.

Nash notes that this return to honesty and accessibility happened to be created by “four huge egos.” Of this multi-headed monster, Diltz writes, “Each one is a considerable person with a considerable voice.” His photographs draw forth the individuality of the four men who made this heavenly, if volatile, assemblage.

There’s Crosby, who, Diltz says, was “the little bad boy, the guy with the smile on his face giving you the finger.” In what might be Diltz’s best-known photograph, and one of the greatest hits of rock photography, Crosby holds a joint in one hand and a toy American-flag pistol pointed at his own head in the other. It’s 1970, Crosby (who died last year, at 81) is at his mustachioed, receding-hairline peak, and the image is the perfect visual summation of the man with the personality of a devil and the voice of an angel.

It was Crosby who insisted that, out of all of them, Stills was the best singer, player, and writer—“No contest.” In Diltz’s lens, Stills lives up to his “Captain Manyhands” nickname: a multi-tasking multi-instrumentalist whose virtuosic force propelled the enterprise. Diltz captures him as a workaholic cherub, all blond hair and dimples, always with an instrument in his hands.

Nash is the dashing troubadour, the handsome English boy who—for a time, anyway—captured Joni Mitchell’s heart. In one of the book’s most striking images, Nash and Mitchell are squeezed together in the back of a car en route to Big Bear; she is scribbling in a notebook, and if you look closely, you can discern the lyrics to “Willy,” her ode to Nash from 1970’s Ladies of the Canyon. Diltz calls him a “true gentleman,” one of only three he’s encountered in the music business so far (the other two being Paul McCartney and Garth Brooks).

As for Young, the group’s self-described “floating satellite,” Diltz says he was the “most natural” to photograph. “I loved hanging out at his ranch,” the photographer says. “You’d wake up in the morning, smoke a big fatty, and look at the geese and llamas! We just laughed all the time.”

In Diltz’s images of Young, it’s mischief and humor that prevail, and throughout this remarkable photographic record, there’s an intimacy and candor that no amount of hired-gun “access” could ever approximate. It no doubt helped that Diltz is universally regarded as a great hang and a good egg. “I’m drawn to extreme personalities, and I want to see that, maybe because I don’t have any of that,” he says. “I’m open and friendly and I don’t have issues.”

If there’s a musician he’d love to photograph but hasn’t, it’s Taylor Swift. “What can I say?,” Diltz asks. “She’s a beautiful girl and I’d like her to be mine!” And for all the thousands of images Diltz has captured, he can’t help but ponder the many that have eluded him. “You think about all the billions of other moments when you didn’t have the camera to your eye,” he says. “But I guess I just picked the moments I liked, and it was always curiosity-driven. I’m interested in people and observing them, and the camera is incidental to that. It’s just the end result of observing them—and going click.

CSN&Y: Love the One You’re With is out now from Genesis Publications

Mark Rozzo is an Editor at Large at AIR MAIL and the author of Everybody Thought We Were Crazy: Dennis Hopper, Brooke Hayward, and 1960s Los Angeles