backward, let us say, for perhaps two or three hundred Terran years?"

"Of course--some very excellent ones are available--" He moved toward
the reading table nearby and began punching a selection of buttons.

As Cameron and Joyce moved to follow, Marthasa waved a hand expansively
and started out the other way. "I can see you're going to be set for a
while. I'll just leave you here, and send the car back after I reach the
house. Don't be late for dinner."

They nodded and smiled and turned to Zlenon. The Markovian was watching
them with pin-point eyes. "I wondered if there was any _particular_
problem in which you might be interested," he said calmly. "If there
is--?"

Cameron shook his head hastily. "No--certainly not. Just general
information--"

The Historian turned his attention to the table and began explaining its
use to the Terrans, showing how they could obtain recording of any
specific material they wished to choose. It would appear in either
printed or pictorial form or could be had on audio if they wanted it.
Once he was certain they could make their own selections he left them to
their study.

"This is the best break we could possibly have hoped for," Joyce
whispered as Zlenon disappeared from their sight. "We can get anything
we want in the whole library if I understand the operation of this
gadget the way I think I do."

"That's the way it looks to me," Cameron answered. "But don't get your
hopes too high. There must be a catch in it somewhere, the way they were
trying to shoo us away from coming here."

* * * * *

They punched the buttons for the history of the planet they were on,
scanning slowly from the present to earlier years. There were endless
accountings of trading and commercial treaties between members of the
Nucleus as shifts of economic balance occurred. There were stories of
explorations and benevolent contacts with races on the outer worlds.
Details of their most outstanding scientific discoveries, which seemed
to come with profligate rapidity--

Cameron whipped back through the pages of the histories, searching only
for a single item, one clue to the swift evolution from barbarism to
peaceful co-operation. After an hour he was in the middle of that
critical period when the Council despaired of its inability to cope with
the Markovian menace.

But the stories of commerce and invention and far-flung exchange with
other peoples continued. Nowhere wa