When Muddy Waters declared that the blues had a child and they named him rock & roll, he knew exactly what he was talking about -- rock & roll was very much an outgrowth of the blues. Country, jazz, and gospel all influenced early rock & roll, but the blues were the most important influence of all. And no discussion of rock & roll's blues heritage would be complete without some mention of Chicago, which is where many of the songs on When the Sun Goes Down, Vol. 4: That's All Right were recorded. Not everything on this 72-minute compilation (which spans 1939-1955) was recorded in Chi-Town, and not all of the artists had a Windy City address -- in the '30s, '40s, and '50s, Southern bluesman sometimes traveled to Chicago to record. But it is safe to say that Chicago-style blues is a high priority and that all of the artists helped pave the way for the rock & roll revolution of the '50s -- artists like Memphis Slim, Arthur "Big Boy" Crudup, Tampa Red, Roosevelt Sykes, and Big Maceo Merriweather. This disc has its share of songs that became standards, including Merriweather's "Worried Life Blues," Austin Powell's "I'd Rather Drink Muddy Water," and Crudup's "That's All Right" (which became a hit for Elvis Presley in the '50s). Other highlights of the disc range from Lil Green's 1941 version of Joe McCoy's "Why Don't You Do Right" (which Peggy Lee didn't embrace until 1943) to Little Richard's 1951 recording of "Get Rich Quick." The latter is downright fascinating. Although "Get Rich Quick" was recorded four years before Richard's commercial breakthrough and isn't as guitar-oriented as his subsequent work, he already had a recognizably flamboyant vocal style. Blues and rock & roll enthusiasts are both advised to give this fine CD a close listen. ~ Alex Henderson, Rovi