The famous Max and his sister, Ruby, are the stars of this self-proclaimed brand-name production—A Max & Ruby Picture Book- -but there is no formula here—only extreme originality. To celebrate their grandmother's birthday, Max is constructing an earthworm cake while bossy Ruby declares that a real cake will be made. She begins whipping one up. Max, in the meantime, breaks the eggs, the first in a series of mishaps that lends repetition—the soul of story hours—to the plot. List from Ruby in hand, he is sent to the store each time he destroys an item, and attempts to add (in a preschooler's version of handwriting) his own sought-after ingredient, Red-Hot Marshmallow Squirters. Each time, the grocer understandably cannot read Max's writing; each time Max returns home, he finds that Ruby is attempting to keep accidents to a minimum by keeping him away from her work. At one point, she posts a drawing in which Max appears inside a red circle with a line through it. Wells's ingenuity never flags, not in the brief text nor in the illustrations. Her close-ups of destroyed ingredients and her many ways of showing two children in the same setting suggest she knows her subject well. Ruby's sloping iced cake is a gem, and Max's is grandly icky and visibly worm-infested: ``Grandma was so thrilled, she didn't know which cake to eat first.'' (Picture book. 3-7)