12 X 5 includes material recorded by the Stones at Chicago's Chess Studios (home to the band's idols Muddy Waters and Howlin' Wolf) on their first US tour. Though this document of the group's early R&B period kicks off with a couple of covers from unsurprising sources (Chuck Berry's "Around and Around,") Mick and Keith waste little time in displaying their own compositional acumen. The acoustic-based, bluesy "Good Times, Bad Times" harkens back to even earlier, more seminal Stones influences than Berry, as does the instrumental "2120 South Michigan Avenue," where the blues-obsessed Jagger's harp is featured a la his hero Little Walter. The downbeat, Arthur Alexanderish "Congratulations" is an effective expression of romantic melancholy, complete with acoustic guitar solo. The slide guitar chords on "Grown Up Wrong" echo another early blues influence, Elmore James. The milestones on this album are two R&B covers to which the Stones take more than a rote approach, "It's All Over Now" and the majestic "Time Is On My Side," which they make completely their own.