Look closely at each illustration—what do you see? Are you sure? Don’t trust your eyes too quickly, because every picture here has an optical trick to fool you. Some-times you’ll find “two objects in one”; sometimes you have to rotate drawings to solve the puzzle. Among the forms of visual magic: a bird that “flies” into a cage and a boy who changes into a monkey when the page is turned upside down. More than 300 engrossing optical illusions.