The Mermaid Parade, a summer solstice ritual to open the beach season at Coney Island, started in 1983 as the revival of an older festival. Greenberg paints detailed--and accurate--layouts of the neighborhood, complete with shops, arcades, the F train to Coney Island, Astroland, and diverse people decked out in their sea-creature finery. She lavishes each joyful spread with upbeat colors and patterns. Skies echo the changing blue tints of...