An intriguing compilation of optical illusions: images that sort themselves out when studied or that can be read more than one way; op art; an Escher; pictures that gain a third dimension when viewed through the special glasses provided, etc. Several of these have appeared elsewhere, but it's instructive to have them together in this handy eight-inch square book--especially with Thomson's brief but lucid explanations of what is happening when the eye and mind try to decipher images that are designed to confuse them. A dandy introduction to the concept of perception. (Nonfiction. 9-12)
