Gone Today, Here Tomorrow?

Pox Americana: The Great Smallpox Epidemic of 1775-82 By Elizabeth Anne Fenn, Hill and Wang, 2001, 370 pages: $25.00 Scourge: The Once and Future Threat of Smallpox By Jonathan B. Tucker, Atlantic Monthly Press, 2001, 291 pages: $26.00 The Demon in the Freezer: A True Story By Richard Preston, Random House, 2002, 240 pages: $24.95