In the second of the Enid and Lester Morse Historic Design lecture series, Dr. Carolyn Sargentson will be lecturing on the theme of secrecy in seventeenth- and eighteenth-century Paris, looking at the role of locksmiths in protecting the affairs of the heart, the home, and of politics, and revealing some of their strategies for developing the perfect high-performance lock. Our use of keys, whether unlocking a building or a computer, is second nature, yet we rarely think about the technical challenges involved in concealing the best-kept secrets of the past.