Notes
First published as a serial in Astounding magazine in 1954.

Publisher's Blurb
WANTED: terrestroid planets, habitable but uninhabited, clean of major sicknesses, rich enough to support colonists without outside help –

FOUND: in almost a generation, nothing –

Then a shipful of astronomers chanced on the Troas-llium system. The Da Gama had set out, but never come home. Now, seven years later, the Henry Hudson is due to leave on the same mission...