This guide covers government surveillance and digital privacy for defense counsel, prosecutors, judges, and privacy practitioners. Part 1 sets out the Fourth Amendment framework and the third-party doctrine. Part 2 covers the modern digital cases. Part 3 covers the Wiretap Act. Part 4 covers the Stored Communications Act. Part 5 covers pen registers and provider assistance. Part 6 covers foreign intelligence authorities. Part 7 covers device searches and compelled decryption. Parts 8 through 15 cover location techniques, aggregation, purchased data, border searches, litigation strategy, remedies, state law, and practice guidance.