One day at his Los Angeles home, Glenn Frey received a package in the mail from Jack Tempchin, the San Diego songwriter responsible for the Eagles’ breakthrough hit “Peaceful Easy Feeling.” The package included a tape demo of “Already Gone,” an anthem about leaving a sour relationship behind for better days. “That’s me being free,” Frey said of the song. He and the rest of the Eagles needed that freedom. Early sessions for the band’s third album were a “disaster area,” said their producer Glyn Johns, who’d been hesitant to work with the Eagles from the start. By the time On the Border got underway, Johns’ relationship with the group had soured: He didn’t think the band members should abandon their country-folk roots, Frey resented Johns’ no-substance policy in the studio, and Don Henley was unhappy with the way Johns had recorded his drums. After six unproductive weeks, the band members packed their bags and headed back to LA, where they found a new producer: Bill Szymczyk, who’d worked with the James Gang and produced Joe Walsh’s solo albums. Szymczyk would help turn the Eagles into the biggest band in the world, encouraging them to get louder and funkier. The result was 1974’s On the Border, the Eagles’ sound-shifting third album. The band members are clearly having a blast on such tracks as “James Dean”—a rowdy tribute to the tragic movie star, co-written with Jackson Browne—and “Midnight Flyer,” a banjo-laden stomper sung by Randy Meisner. Bernie Leadon, meanwhile, contributed “My Man,” a tribute to Gram Parsons, whom Leadon had played with in The Flying Burrito Brothers. Still, if the Eagles wanted to become a real rock band, Szymczyk thought, they needed another guitarist. He recommended Don Felder, who’d toured with David Crosby and Graham Nash. The band invited Felder to play slide guitar on “Good Day in Hell”—with memorable results. “With every take, he just blew us all away,” Frey said. “If he isn’t Duane Allman reincarnate, I don’t know who the fuck is.” On the Border ends with “The Best of My Love,” an acoustic ballad inspired by Henley’s breakup with girlfriend Suzannah Martin. It became the band’s first chart-topping song in the United States—but there was one hiccup. According to the book To the Limit: The Untold Story of the Eagles, the label had edited the single down to under four minutes, without telling the band. Henley was furious, and attempted to have the single pulled from record stores. When the song sold a million copies, Eagles manager Irving Azoff sent the band a gold record with a piece of the record chopped out.