This textbook provides a unique lens through which the myriad of existing Privacy Enhancing Technologies (PETs) can be easily comprehended and appreciated. It answers key privacy-centered questions with clear and detailed explanations. Why is privacy important? How and why is your privacy being eroded and what risks can this pose for you? What are some tools for protecting your privacy in online environments? How can these tools be understood, compared, and evaluated? What steps can you take to gain more control over your personal data? This book addresses the above questions by focusing on three fundamental elements: * It introduces a simple classification of PETs that allows their similarities and differences to be highlighted and analyzed; * It describes several specific PETs in each class, including both foundational technologies and important recent additions to the field; * It explainshow to use this classification to determine which privacy goals are actually achievable in a
