The dominant gene in the DNA of rock ’n’ roll comes from the blues, which is just one reason why many believe it’s the most important musical genre of the last 100 years. Everyone from Chuck Berry to The Beatles to Led Zeppelin has used the basic 12-bar blues chord progression as the underlying structure for their music. Indeed, it’s difficult to imagine much of contemporary music without it. Cognizant of this fact, the Rock and Roll Museum inducted blues legend Robert Johnson into its Hall of Fame in 1986, the institution’s very first year. The following year it added Johnson acolyte Muddy Waters to its ranks, along with bluesmen B.B. King and Big Joe Turner. In subsequent years, blues artists such as Lead Belly, Bessie Smith, Ma Rainey, Howlin’ Wolf, John Lee Hooker, Jimmy Reed, and Willie Dixon, among others, have been inducted into the hallowed hall. For vinyl record collectors, blues records are particularly appealing because the style spans so many years and formats. For example, collectors of antique 10-inch 78 RPM discs on Okeh and other labels look for Bessie Smith tunes such as “Safety Mama” or “Blind” Lemon Jefferson songs like “How Long, How Long.” In the 1920s, Jefferson’s music was so popular that some of his records enjoyed as many as 750,000 pressings. The Depression knocked some of the stuffing out of the blues market, and World War II forced many labels to cease operations altogether as raw materials were husbanded for the war effort. But a parallel upheaval was happening in the blues, as artists moved from the Mississippi Delta region in the south to urban areas up north. In Chicago, Muddy Waters, Howlin’ Wolf, and John Lee Hooker all made their mark, trading their acoustic Martin guitars for electric ones made by Gibson and others (B.B. King’s black ES-335, which he named Lucille, remains one of the most identifiable instruments in music). One of Chicago’s leading blues artists was Willie Dixon. He performed extensively in the postwar era, but he also wrote a lot of tunes recorded as 45s on Chess Records, by performers from locals Waters and Wolf to England’s Rolling Stones—their 45 single of Willie Dixon’s “Little Red Rooster” was recorded in Chicago for Chess in 1965. In fact, in the 1960s, rock bands would regularly weave blues numbers by Dixon, Lightnin’ Hopkins, and Bo Diddley into their repertoires. First pressings of “East-West” by the Paul Butterfield Blues Band are prized, as are mint mono LPs of the 1966 “Blues Breakers with Eric Clapton” album—the leader of that band, John Mayall, was one of the greatest champions of the U.S. blues in England. Then there were the Yardbirds, a blues-inspired pop outfit that launched the careers of not only Clapton (good luck finding a seven-inch single of their 1965 hit, “For Your Love”) but also Jeff Beck (the U.K. release of “Roger the Engineer” is much sought after) and Led Zeppelin’s Jimmy Page (look for “Little Games”).