|Mayflower-Dell paperback, 1963. Cover artist uncredited.|
"That the Nipe had embarked on its incredible career of robbery and murder had been, more or less, an accident. After all, it was a civilised being of high intelligence, intent only on establishing contact with the Earth's real people. These pitiful creatures with only two eyes and four limbs, with their very slow reflexes and their savage weapons, couldn't be the ruling life form! Why, they didn't even keep the customs - and any civilised species must surely adhere to ritual."
Another double, I prefer my American Lancer paperback edition - incidentally, Darrel T. Langart is a pseudonym and anagram of Randall Garrett.