Surprisingly, there isn’t a “beautiful pea-green boat[ful]” of illustrated renditions of Lear’s most famous and favorite verse, making Mortimer’s version with her signature style of handsome, whisker-realistic cat images a perfect marriage to the tale. Her delicate lines, tactile textures of feathers and fur, engaging composition and fascinating borders infused with flowers, ferns, insects and butterflies breathe life into the rhyme. Two styles of borders play off each other effectively; round insets appear like portholes while rectangular ones nicely frame a scroll-like message with text. Other illustrated depictions are less elegant: Hilary Knight’s and Michael Hague’s are typically wry and darkly fanciful; Jan Brett also relies on brightly colored borders, but Mortimer’s palette is richer, more refined and dreamy in atmosphere. Like the title characters, the art walks “hand in hand” with the 22-line poetic romance as this delightfully charming creation does, indeed, “dance by the light of the moon.” (Picture book/poetry. 4-8)