Book excerpt: The Complete Idiot's Guide® to Geocaching, Second Editionis a comprehensive yet entertaining and easy-to-understand book for getting started and having fun with geocaching, a high-tech version of hide and seek for global positioning system (GPS) users. The basic idea is individuals and organizations setting up caches all over the world and sharing the locations of these caches on the Internet. GPS users then use the location coordinates to find the caches hidden in city and state parks, outside buildings, alongside hiking trails, and even in local neighborhoods. In this edition, Waymarking and Wherigo (pronounced 'where I go') are also covered. Waymarking enables GPS users to catalog and record their favorite locations and share them with others, build communities around categories of interesting and unique places or things. Wherigo, which works with Geocaching, is a Beta platform that enables users to create basic tour guides or complicated interactive adventure games using the real world as a backdrop. In The Complete Idiot's Guide® to Geocaching, Second Edition, readers will find- A complete explanation of the game, along with Waymarking and Wherigo, two new GPS games. Expert tips from the founders and operators of the most popular geocaching website. Solid advice on purchasing and using a GPS unit to locate treasures (caches) Valuable information on how to create your own online geocaching profile. Basic rules and game variations. Practical guidance on safety and accessibility issues, along with commonly accepted do's and don'ts. Helpful ideas on finding or starting a local geocaching group, forum, and competition Tricks for geocaching without a GPS unit (using a map and compass) The future of geocaching and GPS gaming.