English guidance on geocaching, a sport where people use GPS (global positioning systems) receivers to hunt for hidden caches located at precise geographic coordinates. There are an estimated 100,000 geocaching sites all over the world. The market for GPS receivers is exploding, with entry-level models now priced at only $100 and online mapping software available for free. This book explains how to navigate geocaching Web sites, use a GPS receiver as well as a map and compass to home in on a cache, log a find and add something to a cache, create a new cache, and even use geocaching as a school project.