As the people of Earth develop atomic power, they are recorded as having achieved maturity by the Galactic keeper of records. But when the keeper learns that they have not yet penetrated space, and that they test their atomic weapons on the planetary surface, he strikes them from the record, commenting that Earth people are 'Silly Asses'.

A collection of 20 classic short stories by Isaac Asimov, author of the Foundation series, featuring the definitive and only in-print version of “Nightfall”.

A research spaceship from Earth lands on Saybrook's Planet to investigate a report by an earlier colony ship. The colony ship's captain, Saybrook, had reported that the planet's abundant plant and animal life was all part of a single organism with a unified consciousness. That organism was able to induce pregnancy in all the colony ship's female animals, and all the offspring born had green patches of fur instead of eyes, a sign that they were part of the planetary organism.

Only a few know the terrifying truth - an outcast Earth scientist, a rebellious alien inhabitant of a dying planet, a lunar-born human intuitionist who senses the imminent annihilation of the Sun... They know the truth - but who will listen? They have foreseen the cost of abundant energy - but who will believe?These few beings, human and alien, hold the key to the Earth's survival.

Slim is a boy whose astronomer father is visiting the country estate of an important industrialist. The industrialist's son, Red, has found two strange animals, and he enlists Slim in a plan to turn the animals into a circus act. The astronomer, meanwhile, tells the industrialist that he has been in contact with space aliens who want to open up their world to interstellar trade. Their world needs help, the astronomer says; ever since the atomic wars that destroyed their old civilization, their world has been regressing.