The research that led to this book was the idea of my physics advisor at Caltech, Kip Thorne, who had been involved in some of the controversies discussed in it and saw that it was a story that someone should try to tell. I was fortunate in having an advisor who was so open to the idea that I should combine studies in physics with work in the history of science. I was doubly fortunate in finding a history advisor as able to facilitate my novice efforts in so many ways as Diana Buchwald, now the general editor of the Einstein Papers Project, engaged in editing the Collected Papers of Albert Einstein. After finishing my thesis work, I benefited greatly from a two-year period spent collaborating with Harry Collins, author of Gravity’s Shadow, a history of experimental gravity wave physics, at Cardiff University. Diana made sure I got much excellent advice at an early stage from the first editor of Einstein’s papers, John Stachel. Another physicist turned historian, Peter Havas, who like Kip was centrally involved in much of the history I was studying, was initially skeptical that I could objectively tell this story, given my background and training. Yet he never let this prevent him from helping me in every way he could, in person and by correspondence. I owe a particular debt of gratitude to the many physicists who agreed to be interviewed by me and would like to thank them all. At the end of the book I have provided a table of the interviews and when they took place. They all informed the text considerably, even when they are not quoted xi