The following scholars (again in alphabetical order) have published work that was essential to the completion of this project. While eager to give them due credit, I am aware that they may be chagrined by my work's many excursions from historical truth. Readers who want to know what really happened should buy and read their books, while blaming the errors herein on me: Julian Barbour, Gale E. Christianson, A. Rupert Hall, David Kahn, Hans Georg Schulte-Albert, Lee Smolin, Richard Westfall, D. T. Whiteside.