What if we were all just characters from a book written by Major Albert Knag as a philosophical present for his daughter Hilde's 15th birthday? This is the question that Sophie Amundsen must ask as she tackles the history of philosophy in what begins as a personalized correspondence course for which she never signed up. Coming home from school one day, Sophie finds questions in her mailbox, followed by typewritten pages about philosophy. She also gets strange birthday cards apparently intended for a Hilde Mller Knag in Lillesand, whom she has never met. Through these unusual circumstances, Sophie embarks on the study of philosophy with Alberto Knox—a middle-aged mystery man in a beret—only to discover that she is nothing more than the fictional heroine of a novel (called Sophie's World) about the history of philosophy. Hilde, on the other hand, whom we meet halfway through the book, appears to be a real girl whose father has written a novel entitled Sophie's World. She in turn learns about philosophy by reading about Sophie's study of philosophy, never suspecting that she is merely a character in a book—Sophie's World—written by a philosophy teacher named Jostein Gaarder to teach teenagers the beauty of philosophical discourse. In this long, self- referential novel (to use the word loosely), Gaarder presents philosophy in a clear, cogent way, using Sophie's and Hilde's experiences to illustrate his points. The reader who is expecting something other than a creative textbook, however, will be disappointed. Maybe Gaarder can fool Norwegian youths into learning philosophy, but savvy American kids won't be so easily hoodwinked. Index. (Philosophy/Fiction. All ages)