Bob Dylan once said Jerry Garcia had no equal. Yet the music icon, still worshipped decades after his death, was intimidated by one artist.Jim Marshall, the legendary photographer behind some of music’s most iconic images — including Johnny Cash flipping off the camera at San Quentin and Dylan strolling through Greenwich Village — was one of the few granted the Grateful Dead’s trust. Through his lens, Marshall discovered a different side of the band’s charismatic leader. Marshall, who died in 2010 at age 74, took thousands of photos of the Grateful Dead throughout the 1960s and 1970s. Many of those coveted images — previously unseen by the public — are featured in a new book, "The Grateful Dead by Jim Marshall: Photos and Stories from the Formative Years, 1966–1977." They were uncovered by Amelia Davis, Marshall’s assistant of 13 years and now owner and manager of Jim Marshall Photography LLC.GRATEFUL DEAD’S ‘HELL IN A BUCKET’ DUCK GOT DRUNK ON SET, PAL POINTS TO WHO LIKELY MADE IT HAPPEN"There was one photo that surprised me," Davis told Fox News Digital. "[Garcia is] in a red sweater, and then there’s [his ex-wife] Mountain Girl in the middle, and then there’s Mike Bloomfield on the side. What we discovered from interviewing Mountain Girl [about the photo] is that Jerry Garcia actually felt threatened by Michael Bloomfield as a musician.""Jerry Garcia was a great musician and guitar player – everybody looked up to him and thought he was so great," Davis said. "So it was interesting to find out that he was intimidated by another musician at the time, who was Michael Bloomfield. It shows that he was human and had fears like anybody else.""He didn’t want to be overshadowed by Mike Bloomfield," Davis added.When the Grateful Dead formed in 1965, they already knew of Marshall, the East Coast photographer who quickly earned the respect of jazz greats like Miles Davis and John Coltrane. In San Francisco's Haight-Ashbury neighborhood, Marshall stood out in his Brooks Brothers white Oxford shirt, penny loafers and fitted jacket. He "stuck out like a sore thumb" among hippies, said Davis.Marshall was soon welcomed into the scruffy jam band’s inner circle. It was no secret among them that Garcia was often nervous playing around Bloomfield, a music force of the era and someone whom Garcia hailed as one of the greatest guitarists of his lifetime.CLICK HERE TO SIGN UP FOR THE ENTERTAINMENT NEWSLETTER"They were all friends, so it’s not like they didn’t like each other," Davis explained. "They all hung out and played together. But the Grateful Dead were an improvisational band. They could really play songs just right at that moment. If they played the same song the next night, it would not be the same because they based their playing on the vibe of what was happening. And Mike Bloomfield was great at improvisational playing, too.""Jerry was intimidated when they played together," Davis said. "Mike Bloomfield could play just as well as Jerry, if not better sometimes. And I think that’s what really intimidated him."In 1968, Bloomfield told Rolling Stone that Garcia’s talent was a sound of its own."I can pick out certain things in what the Rolling Stones play, a few things that I know are exactly the licks that I play," he said at the time. "Then I hear guitar players like Jerry Garcia. He sounds amazingly like he’s trying to sound like me, but I don’t think he is. I think he came that way himself."For Marshall, the band’s rise was a long, strange trip."We were looking through these photographs and here was one where they’re just cracking up, and they’ve got pieces of paper," Davis said. "We wanted to figure out what was going on. We reached out to [bandmates] Phil Lesh, who was still alive when we were putting this book together, and Mickey Hart. They said, ‘Great photograph, but we don’t remember anything.’"LIKE WHAT YOU’RE READING? CLICK HERE FOR MORE ENTERTAINMENT NEWS"I remember on the back of this printed photograph was the inscription ‘Grateful Dead prior to dosing process server,’" she continued. "They got sued all the time… if you look closely, they’re legal papers. It’s the process server serving the Grateful Dead. And they were dosing. That’s just what the Grateful Dead did all the time.""Jim used to say, ‘I learned my lesson to never eat or drink anything when I was around the Grateful Dead," Davis chuckled. "Jim had gotten dosed a couple of times. And he would always say, ‘No way, I’m not going to do that anymore."Looking through the images, Davis said that Garcia wasn’t the only artist who became vulnerable in front of Marshall."I came across a photo of Ron ‘Pigpen’ McKernan by himself, walking down the street," she said. "It was just so moving because Pigpen always felt like the outsider in the group. "He always felt like he was not a part of the group, even though everybody considered Pigpen the heart and soul of the Grateful Dead. But he was more into blues. In the beginning, the band did a lot of blues and jazz. And then they really went hard into rock ‘n’ roll and went in a different direction. Pigpen didn’t want to go in that direction. He was more hardcore blues. So he really felt left out and alone.""I think that photograph of Pigpen just walking down the street by himself is so moving," Davis continued. "It shows how he felt. Jim was able to capture that emotion, that feeling, in a photograph. You don’t even have to say anything, and you feel that isolation. And I think Jim could also relate to that photograph because Jim himself really felt like an outsider. I think in some ways, that photograph reflects how Jim felt about himself, too."McKernan died in 1973 at age 27 from a gastrointestinal hemorrhage.Despite finding themselves in the glaring spotlight, the Grateful Dead weren’t fazed by fame."They were always very community-oriented," Davis said. "They always wanted to include the people, the community that followed them, lived with them, listened to them. They really wanted to make a connection. So how did they navigate fame? They stayed true to themselves. They didn’t compromise that. And that’s why some of their songs would be an hour long — they just got so into the music, spontaneous music really. It’s who they were. And in doing that, they influenced a whole generation of jam bands."Along the way, there was Marshall photographing them."What was it like being with the Grateful Dead? They joked around," Davis said. "They loved to do practical jokes and play around. And Jim witnessed that. He became part of that family… I think trust was big for the band. They knew Jim would never betray their trust. And that’s why they opened themselves up to him.""For many people, the Grateful Dead are heroes, they’re gods," Davis reflected. "But they were human, like you and me. They had their hopes and fears like anyone else. And along the way, they were having fun."