Publisher: Signet, 1963, 175 pgs.
A very nice Mass Market Paperback, squared, well bound with the previous owner's name written on the front free end paper. 2nd Printing. Rubbing to the spine hinges and cover edgewear. "Earth was being invaded by aliens and the top security agencies were helpless: the aliens were controlling the mind of every person they encountered. So it was up to Sam Cavanaugh, secret agent for a powerful and deadly spy network, to find a way to stop them--which meant he had to be invaded himself! "
