Man of Earth.
Earthman!
CHAPTER II
Assignment: Rocket Base
Rick turned the phrase over and over in his head, trying to make sense out of it. Earthman? Who wasn't an earthman? The whole human race was composed of them. Of course ordinary people didn't refer to themselves as homo terrestrialis, but that's what they were just the same.
Scotty was just as puzzled. "Do you make anything out of it?" he inquired.
Rick shook his head mutely.
As Barby made a beeline for the library, Scotty called after her, "Where are you going? It's lunchtime."
She answered without pausing. "I'm going to consult the dictionary before Dr. Gordon comes down."