They're hidden in city and state parks, outside of nearby buildings, alongside hiking trails and exercise routes, and even in local neighborhoods. This is geocaching, an adventure-based game involving intentionally hidden treasures, i.e. caches, and a standard handheld global positioning system (GPS) unit. The idea behind geocaching is for people to set up caches all over the world, and to then share the GPS coordinates of the caches via the Internet. GPS users can then use the location coordinates to find the caches, and once found, a cache usually provides its visitor with a wide variety of rewards available for the taking. Authored by a renowned expert on GPS usage and the editors of Geocaching.com, The Complete Idiot's Guide to Geocachingis a comprehensive yet easy to understand guide for getting started and having fun with geocaching.