Country music has as many strains as the Mississippi River has tributaries. Many credit singer-guitarist Jimmie Rodgers with originating the country-music style—his style mixed the blues and even some jazz with a kind of hillbilly yodeling. The shellac 78s he recorded for Victor and Bluebird in the late 1920s and early ’30s, particularly his 13 “Blue Yodel” tunes, are classics of the early country sound. The Carter Family was another country pioneer, adding ringing fiddles to their arrangements and pulling from gospel and folk traditions. Discovered by the same scout as Mississippi’s Jimmie Rodgers, the Virginia-based group had a million-selling-hit in 1928 with Wildwood Flower.” They were also known for “Will the Circle Be Unbroken” and “Keep on the Sunny Side,” which became the theme song of their radio show. Hank Williams was perhaps the biggest star of the pre-and postwar years. His mournful love songs (“Lovesick Blues,” “Your Cheatin’ Heart”) were balanced by more-cheerful fare (Hey Good Lookin’,” “Jambalaya”). His diversity made Williams a favorite of radio listeners and visitors to Nashville’s Grand Ole Opry alike. By the 1940s, as country music became more mainstream and pop oriented, traditionalists struck out down a little-explored tributary called bluegrass. In bluegrass, soothing harmonies and relaxing, back-porch rhythms were replaced by frenzied fiddle playing, lightning-fast runs on the mandolin, and virtuoso banjo picking. Bill Monroe, a singer who accompanied himself on the mandolin, surrounded himself with the best of the best, including Lester Flatt on guitar and Earl Scruggs on banjo. Monroe’s recording career extended from the first years of the 1940s into the 1990s, so his music can be found on 78s, 45s, LPs, and compact discs. One of his most famous early recordings was a 1946 tune called “Blue Moon of Kentucky.” This modest country waltz was made even more famous in 1954, when it was given an upbeat arrangement by Elvis Presley as the B-side of Elvis’ first recording for Sun Records, a 78 called “That’s All Right.” Another tributary in the river was Western swing, which was kind of a countrified version of the big band swing that was popular in the 1930s. This was the music of Oklahoma (Spade Cooley) and Texas (Bob Wills, Buck Owens) transplanted to Hollywood. In the 1940s, Bob Wills and the Texas Playboys appeared in films with Tex Ritter and others. Cooley had a film career, too, as well as his own variety show in the early days of television (Frank Sinatra was one of many guests). In fact, singing cowboys were a mainstay of Hollywood in the 1930s and ’40s. Gene Autry took that title for himself with songs like “Back In the Saddle Again,” but Roy Rogers, who began his career as Leonard Slye with the Sons of the Pioneers, was one of the biggest movie stars of the 1940s. His rendition of the Cole Porter/Robert Fletcher ditty “Don’t Fence Me In” from the 1945 film of the same name is considered one of his signatures. The flip side of songs about the wide open spaces were ballads about cowboys-gone-bad, also known as outlaws. Marty Robbins told tales of murder in the heat of passion (“El Paso”), Johnny Cash sang about unrequited love (“Big River”), and Merle Haggard used a song based on his own years spent in prison as a cautionary tale to others (“Mama Tried”). Two outlaws who performed together but are best known for their solo careers are Waylon Jennings and Willie Nelson. While Jennings got his start with a 1964 vinyl record called “Waylon at JD’s,” on which he covered everyone from Roy Orbison to Bob Dylan, Nelson was known for penning hits for everyone from Patsy Cline (“Crazy” in 1962) to Ray Price (“Night Life,” in 1963).