A woman once rang me up and said, 'Mr. Escher, I am absolutely crazy about your work. In your print Reptiles you have given such a striking illustration of reincarnation.' I replied, `Madame, if that's the way you see it, so be it.'" An engagingly sly comment by the renowned Dutch graphic artist Maurits Cornelis Escher (1898-1972)--the complex ambiguities of whose work leave hasty or single-minded interpretations far behind. Long before the first computer-generated 3-D images were thrilling the public, Escher was a master of the third dimension. His lithograph "Magic Mirror" dates as far back as 1946. In taking that title for this book, mathematician Bruno Ernst is stressing the magic spell Escher's work invariably casts on those who see it. Ernst visited Escher every week for a year, systematically talking through his entire aeuvre with him. Their discussions resulted in a friendship that gave Ernst intimate access to the life and conceptual world of Escher. Ernst's account was meticulously scrutinized and made accurate by the artist himself.