The Double Invaders -- The invasion of Scarta in the all-powerful name of the Space Empire of Zorgan was on. Everything went as predicted. The cities were taken, there was no opposing spacefleet. And yet everything went wrong. For Scarta was a planet different from any other the arrogant Earthmen had invaded. Its peaceful people were tougher, its unarmed cities more impregnable, and its blue skies less placid than any world had any right to be.
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Ace Double Books G-623: The Double Invaders by John Rackham (John T. Phillifent), 1967. Cover art by Ermoyan.If that name is unfamiliar, don’t be surprised. This is the only book cover attributed to this name.