“GRUMP / GROAN / GROWL / BAD MOOD / on the prowl.” This deceptively simple picture book by masters of that form encourages readers to overcome their funks by putting them “inside” and letting them “slide.” Raschka’s broad ink strokes and splashy watercolors depict a curly-haired moppet and a personified bad mood, in the form of a similarly coiffed beast with pointy triangle teeth and a feline tail and claws—a Wild Thing as if drawn by a child. Colors modulate from heated yellows and oranges to cool blues and greens as the child learns to accommodate his monster mood, and the thick lines of the hand-lettered text form pictorial elements around which child and bad mood engage in a highly choreographed dance. While not as narrative as Sendak’s masterpiece, this offering’s emotional punch comes from the same source, young children’s fear of their own powerful feelings. The metaphor here may immediately elude its literal-minded audience, but like its predecessor, its power goes straight to the viscera in a way that will resonate for a long, long time. (Picture book. 3-5)