Art Tatum's performances were kaleidoscopes of style and idea. His breezy improv is on full display in “Over the Rainbow,” where he launches into a melodic run or a new direction of harmony at the drop of a hat, even occasionally bending time like Chopin. And don't be fooled by the title of “St. Louis Blues”—within it can be found melodic gestures reminiscent of Schubert and Debussy.