Useful Knowledge: What will it be for the next millennium? In five symposia, members of the Amer. Philosophical Soc. asked this question in April 1999 at the Society’s Millennium Meet. Contents: (1) Math & Physical Sciences: The Laws of Nature; Our Concepts of the Cosmos, Progress, Prospects & Mysteries; Math & Computing; Global Warming: Does Science Matter?; & The Molecular Biology of Huntington’s Disease; (2): Biological Sci.: Scientists & the Public: An Ambivalent Partnership; Cancer: The Revolution & the Challenges; Wiring the Brain: Dynamic Interplay between Nature & Nurture; & A Neuroscience of Memory for the 21st Cent.; (3) Social Sci.: Nat. Sovereignty & Human Rights; Econ. Becomes a Science -- Or Does It?; & A Millennium of Economics in Twenty Minutes: In Pursuit of Useful Knowledge; (4) Humanities: Art & Architectural History in the 20th Cent.; More Than One Millennium: The Perennial Return of the History of Religions; & Singularity in an Age of Globalization; & (5) The Professions, Arts & Affairs: 100 Yrs. of the Renaissance; Race & Admission to Univ.; Health Care in a Democratic Soc.; & Culture & Democracy in America. Illus.