Useful Knowledge: What Will It Be for the Next Millennium? In five symposia, members of the American Philosophical Society (APS) asked this question in April 1999 at the Society's Millennium Meeting. Contents: (I) Mathematical & Physical Sciences: The Laws of Nature; Our Concepts of the Cosmos, Progress, Prospects & Mysteries; Mathematics & Computing; Global Warming: Does Science Matter?; & The Molecular Biology of Huntington's Disease; (II): Biological Sciences: Scientists & The Public: An Ambivalent Partnership; Cancer: The Revolution & the Challenges; Wiring the Brain: Dynamic Interplay betwen Nature & Nurture; & A Neuroscience of Memory for the 21st Century; (III) Social Sciences: National Sovereignty & Human Rights; Economics Becomes a Science--Or Does It?; & A Millennium of Economics in Twenty Minutes: In Pursuit of Useful Knowledge; (IV) Humanities: Art & Architectural History in the 20th Century; More Than One Millennium: The Perennial Return of the History of Religions; & Singularity in an Age of Globalization; & (V) The Professions, Arts & Affairs: One Hundred Years of the Renaissance; Race & Admission to Universities; Health Care in a Democratic Society; & Culture & Democracy in America. Illus.