Pictures of objects on the front and outlines of shapes on the back of sturdy tabs invite precocious toddlers to open the pages.Within, four-line rhyming verses that incorporate the titular refrain include a question and hint about an object, usually but not always bath-related, with that shape. Four common shapes—circle, square, triangle and rectangle—begin, respectively paired with "mommy's pretty ring," a washcloth, the sail on a toy boat, and a bath towel. From this concrete beginning the concepts grow abruptly more abstract. A charming double-page illustration of the toddler protagonist sitting amid shapes floating in the bathtub accompanies the vague text: "What shapes can the water make? / A heart or star? An oval lake? / Water changes shape—it's flowing. / Bathtime Mathtime, let's keep going!" Then one spread and 10 lines of text describe 3-D objects: sphere (a ball), cylinder (a shampoo bottle—notably, not depicted as a cylinder), and cube (blocks). The next spread just shows the light-skinned, pigtailed child splashing in the tub. The note to parents at the end claims that the book will show that bathtime "(including hair washing!)" can be fun, but nowhere in the story are the child's pigtails taken down, much less shampooed. A final rebus provides a review and hurriedly introduces cone and pyramid shapes.This well-meaning math concept book sinks under the weight of too much information, unevenly conveyed—a washout. (Board book. 2-4)