Privacy, in human history, is a relatively recent concept. Nobody had much privacy in the Middle Ages. Even kings and queens lacked privacy: it was an age when crowds watched a queen give birth, and the king received visitors while on the chamber pot. Technology and concepts of privacy grew up together—as both friends and enemies. For example, the late 19th century invention of the candid camera made it possible, for the first time, to take someone’s picture without that person’s consent. This fact was in the background of the classic article by Warren and Brandeis that launched the right of privacy. Today, we have smart phones with cameras, selfies, the Internet, surveillance cameras, and tools that can look through walls, smell through walls, see through walls. Dangers to privacy have multiplied enormously, and we have only just begin figuring how to handle the change. This book is timely as our basic understandings of privacy are challenged by modern technology, changing social mores, and evolving legal understandings that both reflect and reinforce underlying changes in society. It is likely to be of interest to graduate and undergraduate students, scholars, and potentially other professionals with an interest in law and social norms.