Thanks to our editor, Ann Harris, at Bantam for lending us her considerable experience and talent in our efforts to hone the manuscript. To Glen Edelstein, Bantam’s art director, for his tireless efforts and his patience. To our art team, Philip Dunn, James Zhang, and Kees Veenenbos, for taking the time to learn some physics, and then, while not sacrificing the scientific content, making the book look fabulous. To our agents, Al Zuckerman and Susan Ginsburg at Writer’s House, for their intelligence, caring, and support. To Monica Guy for proof-reading. And to those who kindly read various drafts of the manuscript in our search for passages where clarity could be improved further: Donna Scott, Alexei Mlodinow, Nicolai Mlodinow, Mark Hillery, Joshua Webman, Stephen Youra, Robert Barkovitz, Martha Lowther, Katherine Ball, Amanda Bergen, Jeffrey Boehmer, Kimberly Comer, Peter Cook, Matthew Dickinson, Drew Donovanik, David Fralinger, Eleanor Grewal, Alicia Kingston, Victor Lamond, Michael Melton, Mychael Mulhern, Matthew Richards, Michelle Rose, Sarah Schmitt, Curtis Simmons, Christine Webb, and Christopher Wright.