Annette C. Boehm started reading Stepsons of terra by Robert Silverberg (Ace double novel books -- D-311)
blurb: For 500 years the distant Terran colony of Corwin had no communication with Earth. But now the invincible war-horde of the Klodni was on the march and the long-forgotten planet desperately needed Earth's help. Baird Ewing was appointed ambassador, sent to get that help.