Doctor Who: The Mind of Evil: 3rd Doctor Novelisation

Eminent scientist Emil Keller has developed a revolutionary process for the treatment of hardened criminals. His invention, the Keller Machine, is being heralded as a major scientific breakthrough. But Professor Keller is in truth the Master, and the Keller Machine is more than a mere machine. Soon the Doctor, Jo, the Brigadier, and UNIT are involved in a bitter struggle with the Master, an alien mind parasite, and a diabolical scheme to plunge the world into a Third World War.