Interviews for this book were conducted under the journalist ground rule of “deep background.” This means that all the information could be used but I would not say who provided it. The book is drawn from hundreds of hours of interviews with firsthand participants and witnesses to these events. Nearly all allowed me to tape record our interviews so the story could be told with more precision. When I have attributed exact quotations, thoughts or conclusions to the participants, that information comes from the person, a colleague with direct knowledge, or from meeting notes, personal diaries, files and government or personal documents. President Trump declined to be interviewed for this book.