In the early hours of the night, young David Maclean sees a flying saucer land and disappear into the sand dunes just beyond his house. Slowly, all of the adults, including his once loving parents, begin to act strangely.

Author & amateur astronomer John Putnam and schoolteacher Ellen Fields witness an enormous meteorite come down near a small town in Arizona, but Putnam becomes a local object of scorn when, after examining the object up close, he announces that it is a spacecraft, and that it is inhabited...

The residents of a small town are excited when a flaming meteor lands in the hills, until they discover it is the first of many transport devices from Mars bringing an army of invaders invincible to any man-made weapon, even the atomic bomb.

Aliens have landed and are hiding on Earth, but need Earth’s scientists to help them fight an inter-planetary war.

While on a boating trip, Scott Carey is exposed to a radioactive cloud. Nothing seems amiss at first, but several months later Scott realizes that he's shrunk in height by several inches. He sees a doctor, who admits that he's baffled. As Scott continues to shrink, decreasing to three feet tall, he becomes bitter, and lashes out at his wife, Louise. He begins to fear a cure will never be found -- since even as he becomes a national sensation, he's still shrinking.

Starship C57D travels to planet Altair 4 in search of the crew of spaceship "Bellerophon," a scientific expedition that has been missing for 20 years, only to find themselves unwelcome by the expedition's lone survivor and warned of destruction by an invisible force if they don't turn back immediately.

As a result of nuclear testing, gigantic, ferocious mutant ants appear in the American desert southwest, and a father-daughter team of entomologists join forces with the state police officer who first discovers their existence, an FBI agent and, eventually, the US Army to eradicate the menace, before it spreads across the continent, and the world.

When a group of astronomers calculate a star is on a course to slam into Earth, a few days before, it's accompanying planet will first pass close enough to the Earth to cause havoc on land and sea. They set about building a rocket so a few selected individuals can escape to the planet.

An alien and a robot land on Earth after World War II and tell mankind to be peaceful or face destruction.

Postulates the first manned trip to the moon, happening in the (then) near future, and being funded by a consortium of private backers. Assorted difficulties occur and must be overcome in-flight. Attempted to be realistic, with Robert A. Heinlein providing advice.