Earth's colony on Ganymede is under attack. The people of Earth demand reprisal, and the United Nations must take action to protect the interests of the people.
But Ted Kennedy is worried. He has been to Ganymede and seen the "people"; and knows a truth too terrifying to reveal. Only he can convince the leaders of Earth that they are victims of a hoax. His life may be forfeit, but he is determined to live long enough to stop the INVADERS FROM EARTH
Warning: slight spoilers ahead! ...Though I think nothing that will ruin your enjoyment of the book.
Invaders from Earth is an expansion of We, the Marauders
. For an earlier work, it has held up fairly well, and a modern reader has to make only slight allowances for the dated aspects of it. It's set in 2064, and a few of the technological and historical bits need some adjustment. There is some persistence of 50s gender roles: while the protagonist's wife does have a career, she is treated in many ways as the little woman
homemaker. Most of the women in the story are secreteries or receptionists; none are executives. One Silverberg theme that is at the core of this story is a distrust of authority, including the media and large corporations.