The Terra Data — E.C. Tubb

Only Earl Dumarest himself believed that there was ever a planet called Earth. He had been seeking it a long time -- but nobody else at the crowded galactic centre believed in it. During his quest he had acquired some bits of information -- a Terrestrial zodiac, an authentic painting of Luna, a general series of hints that he was getting closer.

Then he learned of a man on Elysius who knew where Earth was, and who had the special coordinates that would take a starship directly to it.

Though the man was dead, his widow knew where the data lay. But she demanded a price from Dumarest -- a chore that involved a mining expedition which would bring her back a fortune . . . and for him the information he sought.

But the Terra Data would not be so easily come by!