The mere idea of horses that dive could be enough to pique most readers' interest; fortunately, High and Lewin (previously paired for Winter Shoes for Shadow Horse) communicate more than a novelty subject. Their strong sense of time and place—Atlantic City in 1936—permeates every page. Eight-year-old Ivy Cordelia is thrilled to join her father, a photographer, when he spends the summer taking pictures on the boardwalk. She revels in the boxing kangaroos, human cannonballs and, most of all, the horses that, proudly ridden by pretty girls in bathing suits, high-dive into a tank. The girl fantasizes about making the jump herself and, at summer's end, her dream comes true. Like the images in old hand-tinted postcards, Lewin's detailed watercolors blend sepia tones with selective splashes of color. In contrast to the vintage content, Lewin's presentation involves an arresting, up-to-date juxtaposition of cropped "photos," silhouettes and full-bleed illustrations. Oatman effectively articulates for youngsters the summer mecca of the 1930s (the hotel is a "castle-shaped place rising pink and high as a sunrise into blue New Jersey sky") as well as the classic romance of girls and horses. Ages 5-9. (Apr.)