Reading Henry Alford, the most graceful of humorists, is like being in the hands of a commanding dance partner—a spin here, a dip there, the perfect landing on le mot juste as the music, or sentence, stops. So perhaps his new book, And Then We Danced: A Voyage into the Groove (Simon & Schuster), was as inevitable as it is sublime. It is in one sense a celebration of hoofery in all its wonder and variety, from abandon to refinement. But it is also history, investigation, memoir, and even, in its smart, sly way, self-help. We tag along with Alford as he takes ballet, hip-hop, and tap lessons, dances with Twyla Tharp, visits a ballroom class for reluctant middle-schoolers and another for a lively group of Alzheimer's patients. And Then We Danced is very funny, but more, it is joyful—a dance all its own.