To defend its citizens from harm, must the government have unfettered access to all information? Or, must personal privacy be defended at all costs from the encroachment of a surveillance state? And, doesn't the Constitution already protect us from such intrusions? When the topic of discussion is intelligence-gathering, privacy, or Fourth Amendment protections against unreasonable search and seizure, the result is usually more heat than light. Anthony Gregory challenges such simplifications, offering a nuanced history and analysis of these difficult issues. He highlights the complexity of the relationship between the gathering of intelligence for national security and countervailing efforts to safeguard individual privacy. The Fourth Amendment prohibiting unreasonable searches and seizures offers no panacea, he finds, in combating assaults on privacy-whether by the NSA, the FBI, local police, or more mundane administrative agencies. Given the growth of technology, together with the ambiguities and practical problems of enforcing the Fourth Amendment, advocates for privacy protections need to work on multiple policy fronts.