1 The Pentagon is the world's largest office building, six and a half million square feet, thirty thousand people, more than seventeen miles of corridors, but it was built with just three street doors, each one of them opening into a guarded pedestrian lobby. I chose the southeast option, the main concourse entrance, the one nearest the Metro and the bus station, because it was the busiest and the most popular with civilian workers, and I wanted plenty of civilian workers around, preferably a whole long unending stream of them, for insurance purposes, mostly against getting shot on sight. Arrests go bad all the time, sometimes accidentally, sometimes on purpose, so I wanted witnesses. I wanted independent eyeballs on me, at least at the beginning. I remember the date, of course. It was Tuesday, the eleventh of March, 1997, and it was the last day I walked into that place as a legal employee of the people who built it. A long time ago. The eleventh of March 1997 was also by chance exactly four and a half years before the world changed, on that other future Tuesday, and so like a lot of things in the old days the security at the main concourse entrance was serious without being hysterical. Not that I invited hysteria. Not from a distance. I was wearing my Class A uniform, all of it clean, pressed, polished, and spit-shined, all of it covered with thirteen years' worth of medal ribbons,