with measureless millions of stars, and plenty of
room for more than two intelligent civilizations. It wasn't surprising
that the Lhari, who had only been traveling space for a couple of
thousand years themselves, had never come across humans before. But they
had been delighted to meet another intelligent race--and it was
extremely profitable.

Because men were still held, mostly, to the planets of their own
star-systems. Ships traveling between the stars by light-drive were rare
and ruinously expensive. But the Lhari had the warp-drive, and almost
overnight the whole picture changed. By warp-drive, hundreds of times
faster than light at peak, the years-long trip between Vega and Earth,
for instance, was reduced to about three months, at a price anyone could
pay. Mankind could trade and travel all over their galaxy, but they did
it on Lhari ships. The Lhari had an absolute, unbreakable monopoly on
star travel.

"That's what hurts," Tommy said. "It wouldn't do us any good to have the
star-drive. Humans can't stand faster-than-light travel, except in
cold-sleep."

Bart nodded. The Lhari ships traveled at normal speeds, like the regular
planetary ships, inside each star-system. Then, at the borders of the
vast gulf of emptiness between stars, they went into warp-drive; but
first, every human on board was given the cold-sleep treatment that
placed them in suspended animation, allowing their bodies to endure the
warp-drive.

He finished his drink. The increasing bustle in the crowds below them
told him that time must be getting short. A tall, impressive-looking
Lhari strode through the crowd, followed at a respectful distance by two
Mentorians, tall, redheaded humans wearing metallic cloaks like those of
the Lhari. Tommy nudged Bart, his face bitter.

"Look at those lousy Mentorians! How can they do it? Fawning upon the
Lhari that way, yet they're as human as we are! _Slaves_ of the Lhari!"

Bart felt the involuntary surge of anger, instantly controlled. "It's
not that way at all. My mother was a Mentorian, remember. She made five
cruises on a Lhari ship before she married my father."

Tommy sighed. "I guess I'm just jealous--to think the Mentorians can
sign on the Lhari ship as crew, while you and I will never pilot a ship
between the stars. What did she do?"

"She was a mathematician. Before the Lhari met up with men, they used a
system of mathematics as clumsy as the old Roman numerals. You have to
admire them,