Reeves’ mellifluous, polished sound might seem anything but revolutionary to the contemporary ear. But as a primary mover in the development of what would become known as the Nashville Sound, the singer helped bring country music to pop audiences in the late 1950s by giving his voice—and sound—a cosmopolitan flair. Inspired by Bing Crosby and Frank Sinatra, Reeves, a Texan honky-tonker by birth and training, decided instead to experiment with a velvety crooning style while recording with legendary producer Chet Atkins at RCA. Standing close to the microphone and using the lower register of his baritone, Reeves recorded the intimate, melancholy “Four Walls,” a far cry from the two-step-ready tunes of his early days. The result not only topped the country charts, but reached No. 12 on Billboard’s Hot 100—a coup for pop-country crossover. Reeves and Atkins had found a lush, mature new musical formula, one that would be mimicked by most of their peers and form the backbone of numerous Reeves LPs and hit songs like “He’ll Have to Go.”