Earth's Destruction and Human Colonies

Earth had been destroyed, but man had built his colonies on Mars and Venus and the far-flung moons of Jupiter and Saturn.

Mutation and forced breeding had changed these people so they were no longer human.

The Last Man on Earth

Clyde Lester, the last man on Earth, had a special problem.

Strange Radio Signals from Space

From somewhere in space there originated strange radio signals which could only come from beyond the orbit of Pluto, the outermost planet.