On Venus: An ancient and powerful Venusian race finds its ultimate evolution - but can they accept it?

On Mars: The people of the Fourth Planet are eminently reasonable in all things - except for the cult of the Sacred Martian Pig, for which ''fanatic'' would be entirely too reasonable a word.

And on Earth: On the unknown world of one or ten centuries from now, the strangest stories of all become haunting, fascinating reality, as we find out that human beings are, after all, the most alien of creatures . . .