The Brains of Earth

The Brains of Earth (also called Nopalgarth) is a science fiction story by Jack Vance published in 1966.

This is among many Cold War-era stories that used tales of alien takeovers of people's bodies as an allegory for the paranoia about Communist mind control of the West.

They decide to take the fight to the home planet of the nopals, a world they call Nopalgarth.

They return Burke to Earth with 100 kilograms of gold and plans for the "denopalizer", the device they use to dislodge the parasite by inflicting terrible pain on the host.

Burke recruits Dr. Ralph Tarlbert, his friend and colleague, though with great difficulty, as every other human being is hostile to him.