Fats Waller, the most famous of these, ranks among the most skilled entertainers of the first half of the twentieth century, but his boisterous singing and patter never make you miss his keyboard skills. He could mix impressionistic elements drawn from classical music into his playing, or score a hit with a finely crafted pop song, but the stride aesthetic is always at the heart of his music—especially in solo piano works such as “Viper’s Drag” and “Alligator Crawl.”