Ironically, whereas Yolen takes time off from her self-consciously exquisite fairy tales for the sort of precious but diminutive bauble you'd associate with Zalben, the illustrator suits her style to Yolen's usual elegance. Though it looks longer, the text is mainly a series of ten couplets--from "One little mouse in great distress/ Looks all over for a floor-length dress" to "Ten little porcupines set up a racket,/ As they fight for the velvet evening jacket"--in which various small creatures search, sort, clamor and wail for specific items of clothing to wear to the butterfly ball for which a winged little elfin figure delivers invitations. But as each new set of animals is introduced all the previous lines are reiterated, and Yolen adds two final lines bringing them all to their destination: "Knock knock. . . Who's come to call?/WE HAVE! We've all come to the Butterfly Ball." Zalben's delicate fine line animals scurry in preparation--and cavort on arrival--within, amidst and upon rainbow colored swirls, patterened numerals and sheer decoration. Her watercolors do clothe the whole enterprise in finery well suited to such an occasion; the question is whether Yolen offers enough entertainment to justify the fancy dress.