The advent of online, cellular, and other digital networks has enabled today's government surveillance operations to become more extensive and far more thorough than any other programs before them. Where does the line between taking actions to help ensure the safety of the general population against terrorism and other threats and the privacy of individual citizens lie? Is there any such clearly defined line anymore? This two-volume set examines the key issues surrounding government surveillance and privacy in 21st-century America, covering topics ranging from the surveillance conducted during colonial days, which inspired the Fourth Amendment, to the new high-tech developments that pose unprecedented potential challenges to the privacy of millions of Americans. Readers will gain insight into the complex challenge of interpreting the Fourth Amendment protections against warrantless, unreasonable government searches and understand how changes in the methods by which the U.S. government carries out counterterrorism and law enforcement activities influence its relationship with American citizens and businesses.