Book excerpt: Although privacy is one of the core tenets of librarianship, technology changes have made it increasingly difficult for libraries to ensure the privacy of their patrons in the 21st century library. This authoritative LITA Guide offers readers guidance on a wide range of topics, including • Foundations of privacy in libraries • Data collection, retention, use, and protection • Laws and regulations • Privacy instruction for patrons and staff • Contracts with third parties • Use of in-house and internet tools including social network sites, surveillance video, and RFID