Accordingly, I would like to thank Dale Amon, David Anderson, Alice Barkan, James Bennett, David Blackwell, Kenneth Boulding, Joe Boyle, Stephen Bridge, James Cataldo, Fred and Linda Chamberlain, Hugh Daniel, Douglas Denholm, Peter Diamandis, Thomas Donaldson, Allan Drexler, Hazel Drexler, Arthur Dula, Freeman Dyson, Erika Erdmann, Robert Ettinger, Mike Federowicz, Carl Feynman, David Forrest, Christopher Fry, Andy, Donna, Mark, and Scott Gassmann, Hazel and Ralph Gassmann, Agnes Gregory, Roger Gregory, David Hannah, Keith Henson, Eric Hill, Hugh Hixon, Miriam Hopkins, Joe Hopkins, Barbara Marx Hubbard, Scott A. Jones, Arthur Kantrowitz, Manfred Karnovsky, Pamela Keller, Tom and Mara Lansing, Jerome Lettvin, Elaine Lewis, David Lindbergh, Spencer Love, Robert and Susan Lovell, Steve Lubar, Arel Lucas, John Mann, Jeff MacGillivray, Bruce Mackenzie, Marvin Minsky, Chip Morningstar, Philip Morrison, Kevin Nelson, Hugh O'Neill, Gayle Pergamit, Gordon and Mary Peterson, Norma and Amy Peterson, Naomi Reynolds, Carol Rosin, Phil Salin, Conrad Schneiker, Alice Dawn Schuster, Rosemary Simpson, Leif Smith, Ray Sperber, David Sykes, Paul Trachtman, Kevin Ulmer, Patricia Wagner, Christopher Walsh, Steve Witham, David Woodcock, and Elisa Wynn. Since this list was compiled from imperfect files and heaps of marked-up manuscripts, I apologize to those I may have omitted. Further thanks are due to the members of many audiences, at MIT and elsewhere, for asking questions that helped me refine these ideas and their presentation.

For their help and encouragement, I would also like to thank my agent, Norman Kurz, and my editors, James Ralmes, Dave Barbor, and Patrick Filley. Finally, for contributions of special quality and magnitude throughout this effort, I would like to thank Mark S. Miller and, most of all, Christine Peterson. Without her help, it would not have been possible at all.