Robots and Empire [1_2] by Isaac Asimov (Pam Ward)

Amadiro, the main power of the Spacer worlds. Still bent on revenge for his defeat by Earther Elijah Baley and his robot partners Daneel and Giskard, Amadiro and his accomplices seize on a plan that will irradiate the Earth, killing billions, and leaving the Spacer planets free to colonize the rest of the galaxy.