Are you a maphead? Do you know the symptoms? King of the Mapheads Ken Jennings knows his fellow mapheads. He knows those of us who, in childhood, saved our allowances to purchase an enormous Hammonds world atlas. Jennings knows how we mapheads have all the states and capitals memorized. He can spot us as we longingly, lovingly spend hours pouring over enormous library globes. Maphead-dom is a satisfying existence, we learn, as Jennings transports us to visit with enormous colonies of mapheads, at the London Map Fair, the National Geographic Bee, to the treasure trove of maps hidden in the depths of the Library of Congress.And we are happy to accompany Jennings in this delightful journey chronicled here.