The right to privacy is not mentioned explicitly anywhere in the Constitution. However, a right to privacy is thought to be inherent in the Fourth Amendment’s limits on search and seizure and the Fifth Amendment’s protection against self-incrimination. Moreover, as researcher for USConstitution.net Steve Mount explains, “Supreme Court decisions over the years have established that the right to privacy is a basic human right, and as such is protected by virtue of the Ninth Amendment,” which states that individuals have rights other than those enumerated in the Constitution.

Many critics fear that the right to privacy—perhaps because it is not explicitly protected by the Constitution—is rapidly eroding as advances in information technology make it easier for governments, corporations, and individuals to pry into people’s personal information. Books such...