Mose Allison certainly recognized the uncommon brilliance of pianist Mercy Dee Walton. The young, jazz-based Allison faithfully covered Walton's downtrodden "One Room Country Shack" in 1957, four years after Walton had waxed the original for Los Angeles-based Specialty Records (his original was a huge R&B smash). Walton was a Texas émigré, like so many other postwar California R&B pioneers, who had played piano around Waco from the age of 13 before hitting the coast in 1938. Once there, the pianist gigged up and down the length of the Golden State before debuting on record in ...