Call it a mix of sandpaper and silk if you like, but no vocal duet has ever sounded sweeter. The sheer joy of their contrasting styles—Ella the perfectionist, Louis the naturalist—brings as much pleasure as almost any jazz record ever. Producer Norman Granz, whose taste in rhythm sections was flawless, hand-selected the supporting players here, and the rest—Louis and Ella’s righteous readings of the some of this century’s greatest songs—is simply heaven on earth.