Until now, we've only gotten hints of the musical tastes of the icons of the Marvel Cinematic Universe -- AC/DC on Tony Stark's in-armor playlist, the Falcon turning Captain America on to Marvin Gaye -- but in "Guardians of the Galaxy," audiences get a complete sense of Star-Lord's '60s and '70s-era power-pop leanings -- and, as James Gunn, Chris Pratt and Vin Diesel attest, it's as appropriately awesome a mix tape as the cassette label suggests.

The lineup of songs is epic, in terms of pop touchstones from their era: Swedish rockers Blue Swede's 1974 smash hit cover of "Hooked On a Feeling"; "Go All the Way," the 1972 breakthrough hit for songwriter/lead singer Eric Carmen's early band The Raspberries; "Moonage Daydream," David Bowie's 1971 glam rock ode to an alien messiah; blues rocker Elvin Bishop's "Fooled Around and Fell in Love," from 1971, with vocals by future Jefferson Starship singer Mickey Jones; the ethereal, choir-tinged "I'm Not In Love," 10cc's soft rock chart-topper from 1975; "Come and Get Your Love," a 1974 R&B smash from the Native American group Redbone; 1976's explosive proto-punk "Cherry Bomb," signature song of the all-ladies lineup of The Runaways, co-penned by band member Joan Jett; 1979's ubiquitous "Escape (The Pina Colada Song)" the one major pop hit for future musical theater whiz Rupert Hine; the uplifting soul staple "O-o-h Child," a 1970 hit for the Five Starships; the bona fide classic "Ain't No Mountain High Enough" from 1967, featuring soaring vocals by Marvin Gaye and Tammi Terrell; and another definitive Motown track from 1969, the high-energy "I Want You Back" by the Jackson 5, featuring then-11-year-old lead vocalist Michael Jackson. (Norman Greenbaum's enduring 1969 gospel/psychedelic rock fusion "Spirit in the Sky" also appears on the soundtrack album, but not in the film.)

Lesser films might have populated their soundtracks with a similar assortment of surefire mood-setters (and download-inspirers), but director James Gunn -- who also developed an orchestral score with longtime collaborator Tyler Bates -- found a way to fully integrate the era-specific music into the plot of "Guardians," using the music to provide an emotional connection for Star-Lord (Pratt) to his late mother, and by association, his long-lost homeworld.

"When I started writing the script, there was a script for my script, and it didn't 100% speak to me, so I wanted to make some pretty major changes and I rewrote the whole script," Gunn told Comic Book Resources. "The very first thing that I thought of was this idea of the Walkman and the cassette tape, which is really this character's connection to his home planet of Earth. And that was the emotional center of the film: the MacGuffin of the film is this orb that everyone's chasing after; the emotional center is this Walkman. It was just a natural part of the screenwriting process.

"All those songs that you see in the movie were all written into the film," Gunn continued. "They're all part of the screenplay, so they were there from the ground floor up." Gunn admits he got to select music that he's been fond of for most of his life. "One of my favorite songs of all time is 'I Want You Back' by the Jackson 5," he says, "And my favorite song in the movie, strangely, is 'Come and Get Your Love' by Redbone, which is when I think the whole idea of the mix tape started cementing."

Cinematically, he's also especially pleased with the use of "Cherry Bomb" as the Guardians gear up for a crucial mission. "I'm such a fan of the Runaways, and right there [the Guardians are] finally getting their courage, their chutzpah, to do something to save the day. It's such a great song for them to kind of prep to."

Recognizing the personal importance of the playlist to Peter Quill, Chris Pratt made a point to absorb every song on Quill's "Awesome Mix Vol. 1" mix tape. "That was one of the first things I requested," says Pratt, "because it was the emotional center of the character and this movie and Peter Quill has been listening to this thing nonstop his entire life. I have a few albums like that in my life, where I know all the words, so I wanted to be that familiar with the music by the time we shot the movie.

"I had them sent to me, and while I was working out, I just listened to it, in order, on repeat. over and over, this album," continued Pratt, whose own tastes didn't line up precisely with Star-Lord's. "Some of the songs I really love -- and some I really fucking hate! And I incorporate sweating on the Stairmaster to [sings] 'If you like Pina Coladas...' I was like, 'Oh, man.' But one song that really worked for me was "O-o-h Child." That has a beats-per-minute that's perfect for my running pace, so when I was running and that song came on, it put me at a nine-minute mile, which at the time was my mile. And I'm like [sings loudly] 'O-o-h child...' Oh, this fucking song! I don't have to listen to the Margarita song again!"

"I loved all the music," declared Vin Diesel, who plays Groot in the film. "I had so much fun with the music -- I thought it was such a testament to the movie. This is the closest Marvel will ever get to a musical, it was that much fun for me. The movie starts with kind of an emotional tone, very quickly, and the music and watching Star-Lord kicking aliens makes you feel like you're going to have a really good time. I'm singing the music every day. Most of the time when I walk into an interview, I start singing, 'Hooked On a Feeling.'

"The coolest thing was my three-year-old son was watching the movie and when 'Hooked On a Feeling' comes on, he was at the edge of his seat,' Diesel added. "This is the first time we've ever gone to a movie together -- obviously, he can't see 'Riddick' or any of the others -- so he kind of scoots to the edge of his seat and he squints his eyes and he starts singing [sings] 'Hooked on a feeling... High off believing..." And watching him do that just melted my heart.

"It's remarkable how a soundtrack can be so important -- so important to the storytelling, so important to the experience," Diesel continued. "I think the music is going to make people see this movie a lot. I think the music's going to make you want to go. You have so much fun in the movie, and it's music that you want to share with your kids anyway, and it's great because of that. I love all the songs. I just thought it was an incredible collection. I wanted Peter Quill's soundtrack."