Matson was annoyed. He had expected more than this, and his
frustration drove him to watch the aliens closely. He followed them,
sat in on their sessions with the scholars at the University, watched
them at their frequent public appearances, and came to know them well
enough to recognize the microscopic differences that made them
individuals. To the casual eye they were as alike as peas in a pod,
but Matson could separate Farn from Quicha, and Laz from Acana--and
Ixtl--well he would have stood out from the others in any
circumstances. But Matson never intruded. He was content to sit in the
background and observe.

And what he saw bothered him. They gave him no reason for their
appearance on Earth, and whenever the question came up Ixtl parried it
adroitly. They were obviously not explorers for they displayed a
startling familiarity with Earth's geography and ecology. They were
possibly ambassadors, although they behaved like no ambassadors he had
ever seen. They might be traders, although what they would trade only
God and the aliens knew--and neither party was in a talking mood.
Mysteries bothered Matson. He didn't like them. But they could keep
their mystery if he could only have the technical knowledge that was
concealed beneath their beautifully shaped skulls.

At that, he had to admit that their appearance had come at precisely
the right time. No one better than he knew how close Mankind had been
to the final war, when the last two major antagonists on Earth were
girding their human and industrial power for a final showdown. But the
aliens had become a diversion. The impending war was forgotten while
men waited to see what was coming next. It was obvious that the
starmen had a reason for being here, and until they chose to reveal
it, humanity would forget its deadly problems in anticipation of the
answer to this delightful puzzle that had come to them from outer
space. Matson was thankful for the breathing space, all too well aware
that it might be the last that Mankind might have, but the enigma of
the aliens still bothered him.

He was walking down the main corridor of the Physics Building on the
University campus, wondering as he constantly did about how he could
extract some useful knowledge from the aliens when a quiet voice
speaking accentless English sounded behind him.

"What precisely do you wish to know, Dr. Matson?" the voice said.

Matson whirled to face the questioner, and looked into the face