From "A Note to the Reader"

IN THE MAIN BUILDING OF the CIA’s sprawling Virginia campus, past the security guards and the detection machines, up a staircase and at the end of a winding corridor that doglegs to the left, is a windowless conference room. There is no name or number on the door. Inside, it has the feel of a space that might be used for a graduate seminar; there’s a whiteboard on one wall and a table long enough to sit a dozen or so intelligence analysts. But there were only two other people seated at the table on the June day when I was there--a distinguished agency historian and a press officer to watch over both of us. I had come with the hope of picking the scholar’s brain about Betty Pack, the British and American secret agent who had done so much to help the Allies win World War II.

It was, for me at least, a tense conversation. The CIA official knew, I suspected, a lot more than he was revealing, and I had the difficult task of trying to pull the information out of him. But he was a shrewd man who had spent a lifetime guarding secrets; he was not about to make an indiscreet revelation to me. Nevertheless, we both seemed to be enjoying the game until he took offense at something I had said.

I had announced that the book I intended to write would be a true story.