Wendy Pfeffer describes the amazing metamorphosis from tiny, jellylike egg, to little fishy tadpole, to great big bullfrog. Holly Keller has created the archetypal frog pond and we see it through the seasons as the tadpoles grow legs and lungs and eventually hop onto land: bullfrogs at last. “Well-designed ink drawings washed with soft-toned watercolors stretch across the double-page spreads, showing the action above and below water level. . . .