Before rock & roll gave listeners the Traveling Wilburys, country music spawned the Highwaymen, a supergroup of mythic proportions that featured living legends Johnny Cash, Willie Nelson, Waylon Jennings, and Kris Kristofferson. The foursome had worked together in various combinations over the years, but teamed up under the Highwaymen umbrella in 1985. Their first single together, "Highwayman," topped the country charts that year and spawned an album of the same name on Columbia. The album also proved mightily popular, hitting number one on the country listings and producing a...