Can you name the capital of imperial Vietnam? This was a question in a recent National Geographic Bee, an annual event that challenges the downward trend in U.S. geographical literacy. These are just a few of the facts collected by Ken Jennings, a life-long Maphead (Scribner, $15), in his exuberant look at all things cartographic. As you would expect from a record-holding Jeapordy! champion, Jennings is well-supplied with trivia. He’s a perfect guide to a subject as diverse as geography; the “ultimate interdisciplinary study,” geography encompasses language, history, biology, public health, urban planning, and, of course, maps. Jennings offers paeans to the early cartographers, working without GPS, and he revels in GPS-enabled games, becoming an avid geocacher. He visits people who travel by checklist, collecting countries, elevations, and even Starbucks shops, then goes on his own road-atlas rally, an exercise that involves staying home. Throughout, he demonstrates how vital a tool a map is, while also savoring it as “a beautiful system in and of itself.”