This book is a guide to the relatively new, and exponentially growing, activity of geocaching. Geocaching is a treasure hunting game, using handheld global positioning system (GPS) receivers, that is now played worldwide. This book covers not only the fundamental principles and points of geocaching, but also covers such related topics as wilderness navigation, hiking, and outdoor safety.Combining the "e;how to"e; information -- the necessary technical background in GPS, navigation, and hiking--along with some history of the geocaching activity, and some narrative color that gives readers a sense of this phenomenon and its participants. The book will be practical, portable field guide to this unusual leisure activity.