George G. Szpiro, PhD, is a mathematician and journalist. He covers Israel and the Middle East for the Swiss daily newspaper "Neue Z�rcher Zeitung", for which he also writes an award-winning monthly column on mathematics. His books include "Poincar�'s Prize: The Hundred-Year Quest to Solve One of Math's Greatest Puzzles" (Dutton).Jeffrey S. Cramer is curator of collections at the Thoreau Institute at Walden Woods, an independent research institution that holds the world's most comprehensive collection of Thoreau-related material. Cramer is the editor of "The Portable Thoreau" (Penguin), "Walden: A Fully Annotated Edition", and "I to Myself: An Annotated Selection from the Journal of… Henry D. Thoreau", among other books.