"It's tough, all right," I said. I took out my pocket knife and opened it and worked on the edge of the paper. Nothing. I went over to the bureau and put the paper flat against the top and sawed at it, putting my weight on the knife. I raised the knife and brought it down hard. I didn't so much as mark the sheet. I put the knife away. "That's some paper, Mr. Foster," I said. "Try to tear the binding," Foster said. "Put a match to it. Shoot at it if you like. Nothing will make an impression on that material. Now, you're a logical man, Legion. Is there something here outside ordinary experience or is there not?" I sat down, feeling for a cigarette. I still didn't have. "What does it prove?" I said. "Only that the book is not a simple fraud. You're facing something which can't be dismissed as fancy. The book exists. That is our basic point of departure." "Where do we go from there?" "There is a second factor to be considered," Foster went on. "At some time in the past I seem to have made an enemy. Someone, or something, is systematically hunting me." I tried a laugh, but it felt out of place. "Why not sit still and let it catch up with you? Maybe it could tell you what the whole thing is about." Foster shook his head. "It started almost thirty years ago," he said. "I was driving south from Albany, New York, at night. It was a long straight stretch of road, no houses. I noticed lights following me. Not headlights--something that bobbed along, off in the fields along the road. But they kept pace, gradually moving alongside. Then they closed in ahead, keeping out of range of my headlights. I stopped the car. I wasn't seriously alarmed, just curious. I wanted a better look, so I switched on my spotlight and played it on the lights. They disappeared as the light touched them. After half a dozen were gone, the rest began closing in. I kept picking them off. There was a sound, too, a sort of high-pitched humming. I caught a whiff of sulphur then, and suddenly I was afraid--deathly afraid. I caught the last one in the beam no more than ten feet from the car. I can't describe the horror of the moment----" "It sounds pretty weird," I said. "But what was there to be afraid of? It must have been some kind of heat lightning." "There is always the pat explanation," Foster said. "But no explanation can rationalize the instinctive dread I felt. I started up the car and drove on--right through the night and the next day. I sensed that I must put distance between myself and whatever it was I had met. I bought a home in California and tried to put the incident out of my mind--with limited success. Then it happened again." "The same thing? Lights?"