But to some people at least the New Chicago Underground symbolizes something far more gloomy. If you're not careful to board just the right train you can get lost in its tomblike, spiraling immensity and feel as helpless as a wandering ghost or an experimental laboratory animal caught up in a blind maze. You can be carried fifty miles in the wrong direction and look out through the windows of a train traveling at half the speed of sound, and see a country landscape or the wide sweep of Lake Michigan five minutes after you've settled down in a comfortable chair and become absorbed in the news of the day on micro-film. You'll stare out and the section of the city where your home is located just won't be sweeping past. You'll have to get off at the next station, perhaps twenty or thirty miles further on, ride back, and board another train. It's seldom quite as frustrating as that, but only because most of the riders have been conditioned to keep their wits about them through a nightmare kind of trial-and-error apprenticeship. You've got to stay alert until you've boarded a train with just the right combination of numerals on its destination plate. It isn't hard to do, unless you're carrying a tiny silver hawk in a wafer-thin case, and your destination may be changed without warning and with unbelievable infamy by someone capable of great evil who would much prefer not to have you board a train at all. I could almost picture him weaving in and out between the platform crowds--faceless so far, but quite possibly glassy-eyed with little waltzing death-heads in the depth of his pupils. An unknown human cipher intent on my destruction, refusing to be discouraged by the failure of a small mechanical killer to do the job for him. If I'd had a strong reason to believe I actually was being followed, if he'd come right out into the open and I could have caught a glimpse of him, however brief, I'd have felt a subconscious relief that would have kept me on guard and confident. It would have given me an edge that not even the fact that I had no gun could have taken away from me. It's the unknown and unpredictable that's unnerving, the realization that invisible eyes may be scrutinizing you from a distance and the brain behind them deciding that it would be a great mistake to let a failure of nerve or concern for the consequences interfere with what had to be done. He wouldn't be wanting me to wear that insignia ever--on Earth or on Mars--and just knowing that made me almost miss my train as it came rushing toward me. The train was so crowded I had to stand, but I had no complaint on that score. In a seat, with people jamming the aisle in front of me, I'd have been wedged in even more securely. In a standing position I could edge forward and back and keep an eye on the passengers who were holding fast to the horizontal support rail on both sides of me. 5