Once again Harold wields his purple crayon, this time intent upon drawing a picture for his room. But Harold's picture with its animals, flowers, and railroad tracks, turns out to be a lesson in relativity for the small child. All at once he is dwarfed by objects which are commonly smaller than he. But, as Harold draws his way back to the comfortable perspective of his room, he becomes alert to the effects of relativity, in a manner as painless and entertaining as any child or adult could wish. Simple vocabulary and the magic of Harold's crayon make this a real inducement to the young child just beginning to read.