Adroitly blended realism and fantasy, [The Ogre Downstairs] … uses the results of magic potions to further compatibility. Caspar, Gwinny, and Johnny detest their new stepfather, the Ogre, and he is indeed detestable: an impatient, self-centered bully; they dislike almost as much his two sons, Douglas and Malcolm…. Sharing troubles and the wrath of the Ogre produces more understanding, and when an angry mother decamps, all unite in an effort to improve the family situation. The Ogre's conversion to comparative sweetness and light isn't quite convincing, but this weakness is outweighed by the strengths of the story: action, variety, humor, strong characterization, and sprightly, polished writing style.