The Visitors
It looked like a big black box-perhaps fifty feet high, two hundred long. And it had settled squarely on forestry student Jerry Conklin's car, parked next to a fishing stream outside Lone Pine, Minnesota.

The townspeople of Lone Pine were the first to see it—and one of them was the first and only human to shoot at it. He paid for his rashness with instant death.

Within hours the press, the government and the public knew something strange had happened in Lone Pine and were beginning to face the incredible possibility that Earth now harbored something from outer space. A machine? An intelligent being? There was no way to know.

But Jerry Conklin knew. The visitor had scooped him up, held him prisoner for hours, then let him go—and he had sensed its thoughts and feelings. Jerry knew the visitor was a living, intelligent creature.

Then more of the giant black boxes descended to Earth, almost all in the United States. And they began eating...and reproducing. The visitors seemed harmless if left alone, but their powers of defense, and their very existence, threatened world stability. The public, the nation's allies—and its enemies—demanded more information. But there was none.

Then Jerry followed up on a rumor and made one more discovery. The visitors were paying for their food and lodging with fantastic gifts. And that payment could destroy Earth's civilization.
American Science fiction
Clifford D. Simak
Clifford Donald Simak (August 3, 1904 – April 25, 1988) was an American science fiction writer. He won three Hugo Awards and one Nebula Award.The Science Fiction Writers of America made him its third SFWA Grand Master,[4] and the Horror Writers Association made him one of three inaugural winners of the Bram Stoker Award for Lifetime Achievement.[5] He is associated with the pastoral science fiction subgenre.