nvironment--the motives behind that
conditioning usually escape us, but that's beside the point--and they
did a thorough job of it. The colonists have had no more than a century
of freedom since the Bees pulled out, and four generations simply isn't
enough time for any subjugated culture to climb from slavery to
interstellar flight."

Stryker made a padding turn about the control room, tugging unhappily at
the scanty fringe of hair the years had left him.

"If they're neither Hymenops nor resurgent colonists," he said, "then
there's only one choice remaining--they're aliens from a system we
haven't reached yet, beyond the old sphere of Terran exploration. We
always assumed that we'd find other races out here someday, and that
they'd be as different from us in form and motivation as the Hymenops.
Why not now?"

Gibson said seriously, "Not probable, Lee. The same objection that rules
out the Bees applies to any trans-Alphardian culture--they'd have to be
beyond the atomic fission stage, else they'd never have attempted
interstellar flight. The Ringwave with its Zero Interval Transfer
principle and instantaneous communications applications is the only
answer to long-range travel, and if they'd had that they wouldn't have
bothered with atomics."

Stryker turned on him almost angrily. "If they're not Hymenops or humans
or aliens, then what in God's name _are_ they?"

* * * * *

"Aye, there's the rub," Farrell said, quoting a passage whose aptness
had somehow seen it through a dozen reorganizations of insular tongue
and a final translation to universal Terran. "If they're none of those
three, we've only one conclusion left. There's no one down there at
all--we're victims of the first joint hallucination in psychiatric
history."

Stryker threw up his hands in surrender. "We can't identify them by
theorizing, and that brings us down to the business of first-hand
investigation. Who's going to bell the cat this time?"

"I'd like to go," Gibson said at once. "The ZIT computer can wait."

Stryker vetoed his offer as promptly. "No, the ZIT comes first. We may
have to run for it, and we can't set up a Transfer jump without the
computer. It's got to be me or Arthur."

Farrell felt the familiar chill of uneasiness that inevitably preceded
this moment of decision. He was not lacking in courage, else the
circumstances under which he had worked for the past ten years--the
sometimes perilous, som