The Alien Years — Robert Silverberg

Fifteen feet tall, the Entities land in cities across Earth. Ignoring humankind, they wall themselves in impenetrable enclaves, enslaving a few willing collaborators with their telepathic PUSH. Then they plunge humans into a new Dark Age without electricity, allowing us to live--but no longer as a dominant species.

But a few refuse to submit to fate, including the Carmichael family, whose patriarch, an aging colonel devoted to resistance, will inspire a daring new generation of dissidents. United in spirit, these diverse rebels--an aging hippie, a cold-blooded Muslim assassin, a prodigal son, and a renegade hacker--will carry on the colonel's legacy as they attempt to kill the mysterious Prime Entity and free the planet.