As technology continues to advance, what was once thought novel, even a luxury, quickly becomes commonplace, even a necessity. Global Positioning System (GPS) technology is one such example. Generally, GPS is a satellite-based technology that discloses the location of a given object. This technology is used in automobiles and cell phones to provide individual drivers with directional assistance. Just as individuals are finding increasing applications for GPS technology, state and federal governments are as well. State and federal law enforcement use various forms of GPS technology to obtain evidence in criminal investigations. For example, federal prosecutors have used information from cellular phone service providers that allows real-time tracking of the locations of customers' cellular phones. This book discusses the basics of GPS technology, society's reliance on it, and some of the related legal and privacy implications, with a focus on the legislative and judicial responses on both the federal and state levels.