When a random pattern of squares suddenly forms a face, when the press-out black-and-white spinning wheel bursts into color, or when special glasses transform a series of dots into 3-D splendor—then visual magic is in the air. These 30 tricks and illusions are delightful, puzzling, and often beautiful. Readers will wonder: are those lines really straight, or are they curved? Is this shape moving…and if so, which way? Could a picture of a goldfish actually vanish from the page? The marvelous images include a 16th-century painting that looks like a bowl of vegetables—until the book’s turned upside down—and Upstairs, Downstairs, M.C. Escher’s fascinating drawing of an “impossible” house. Each illusion offers insight into how our perception works.