As Nashville legend has it, a woman named Hazel Smith devised the label that would be applied to so many generations of country artists. A secretary, publicist, bookkeeper, sober person, and self-described “mother hen” at Tompall Glaser’s studio/hideout Hillbilly Central, Smith got a call from a DJ in North Carolina wanting to know what the heck you called this gritty new sound, led by Willie Nelson, Waylon Jennings, and Kris Kristofferson. She said she’d call him back and pulled out a dictionary, flipping through the entries until she settled on the word “outlaw.”

We could have ended up talking about redneck rock or progressive country or even armadillo country, after the tenacious rodent that became the movement’s unofficial mascot. “Outlaw” stuck not just because that strain of music needed an evocative name; perhaps more crucially, the word describes a philosophy of being and thus creating, rather than a particular sound. Outlaw country became a metaphor for the lifestyle: facing off against the establishment, hiding your contraband from the cops, and touring from town to town as though chased by the law.

Since Smith’s phone call back in ’73, outlaw country has been a source of fascination over who gets to wear that particular cowboy hat, what it sounds like, and where it comes from. These issues abound in an excellent new exhibition at the Country Music Hall of Fame, where a mix of media—videos, recordings, concert posters, and some truly astounding artifacts—provides a very specific idea of what that term meant initially and therefore what it means now. The museum defines the movement as geographically disparate and musically permissive, covering Tennessee to Texas, roadhouse blues to honky-tonk twang to strange new takes on western swing. What the outlaws shared was a rebellion against staid country conventions, over how the music got made and what it should sound like. Waylon campaigned on this platform with 1974’s “Are You Sure Hank Done It This Way?” (sample lyric: “Rhinestone suits and new shiny cars, it’s been the same way for years. We need a change”), and the idea was further cemented by 1976’s odds-and-ends collection Wanted! The Outlaws, featuring Glaser, Nelson, Waylon, and Jessi Colter. It was the first country album certified multi-platinum and remains one of the genre’s most successful crossovers.

While he’s not the biggest name in the exhibition, it’s actually Bobby Bare who emerges as the first outlaw, insofar as he was the first to negotiate full artistic control of his career. By the early ’70s, he was a country music veteran with an enviable series of pop and country hits, from 1966’s “Streets of Baltimore” to 1970’s “How I Got to Memphis.” He persuaded RCA Records to let him pick his own songs, assemble his own band, and even produce his own records. That his subsequent albums—in particular, 1973’s Lullabies, Legends & Lies—became hits meant that labels were willing to extend similar concessions to other artists.

Most of the outlaws had tried their hands at typical label careers in Nashville, but found the experience stifling. Willie Nelson was so despondent over his floundering prospects that one cold night during a set at the legendary Nashville honky-tonk Tootsie’s Orchid Lounge, he lay down in the middle of Lower Broadway and waited for a car to run him over. When none arrived, he picked himself up and played the rest of the show. Following a fire on his pig farm, Nelson relocated to Austin, in his home state of Texas, where he became a figurehead for a new movement that united long-haired hippies and homegrown rednecks.