He had suspected the truth immediately, and when he had seen the woman's handkerchief with the initials "SB" embroidered on it lying by one of the filing cabinets he had known definitely that his quarry was hiding out in his mind. Retiring to his bachelor quarters, he had entered at the same place-time and set off in pursuit. Her only advantage lost, Sabrina York was now at his mercy. Unless she discovered his presence and was able to locate his most recently materialized place-time before he over-took her, her capture was assured. Only two things bothered Blake. The little office was far in his past, and it was unlikely that anyone save the few intimate acquaintances whom he had told about it were aware that it had ever existed. How, then, had a total stranger such as Sabrina York learned enough about it to enable her to use it as a point of entry? The other thing that bothered him was of a much more urgent nature. He had been in enough minds and he had read enough on the subject of Trevorism to know that people were sometimes capable of creating beings considerably higher on the scale of mind-country evolution than ordinary memory-ghosts. One woman whom he had apprehended in her own mind had created a walking-talking Virgin Mary who watched over her wherever she went. And once, after tracking down an ex-enlisted man, he had found his quarry holed up in the memory-image of an army barracks with a ten-star general waiting on him hand and foot. But these, and other, similar, cases, had to do with mal-adjusted people, and moreover, the super-image in each instance had been an image that the person involved had _wanted_ to create. Therefore, even assuming that Blake was less well-adjusted than he considered himself to be, why had he created three such malevolent super-images as Miss Stoddart, Officer Finch, and Vera Velvetskin? * * * * * They followed him off the campus into a vicarious memory-image of Walden Pond, Thoreau's shack, and the encompassing woods. Judging from the ecstatic "oh's" and "ah's" they kept giving voice to, the place delighted them. Once, glancing back over his shoulder, he saw them standing in front of Thoreau's shack, looking at it as though it were a doll's house. Not far away, Thoreau was sitting in under a tall pine, gazing up into the branches at a bird that had come through only as a vague blur of beak and feathers.