Harry Harrison 
Invasion: Earth 

The object appeared over the Pacific, moving so fast that it was over Arizona before the supersonic shock of its passing was felt. It slowed perceptibly somewhere over New Jersey, and took only a small chunk out of the World Trade Center on its way between the two towers. Earth would never be the same again’The Oinn and the Blettr are in league against us. They do not war with each other. The ship that crashed was a plant to make us believe.’ They came from beyond the galaxy, bent on world domination.the alien terror that endangered mankind. They deceived men into believing they sought only peace. And as their battle fleets threatened earth with extinction, only one man could save the human race.