Introduction -- Approaches to secrecy -- Secrecy and moral choice -- Coming to experience secrecy and openness -- Secret societies -- Secrecy and self-deception -- Confessions -- Gossip -- Secrecy, power, and accountability -- The limits of confidentiality -- Trade and corporate secrecy -- Secrecy and competition in science -- Secrets of state -- Military secrets -- Whistleblowing and leaking -- Intrusive social science research -- Investigative journalism -- Undercover police operations -- Conclusion.