In a time in which new technologies make it easy to gather and process data, the discussion on privacy tends to focus exclusively on the protecting of personal data. To Serge Gutwirth, privacy involves far more. He advances the intriguing thesis that privacy is in fact the safeguard of personal freedom--the safeguard of the individual's freedom to decide who she or he is, what she or he does, and who knows about it. Any restriction on privacy thus means an infringement of personal freedom. And it's exactly this freedom that plays an essential role in every democracy.