Henry Kuttner & C L Moore's "Shock" (as by Lewis Padgett) (short story, time travel, free): Curiosity killed the cat!

One fine day, Manning Gregg, the physicist, was at home & saw a hole suddenly appearing in his apartment's wall - a hole from which emerged a curious-looking man! This is the man from future, & he's looking for something in our time.

As Halison, the future man, goes out on his quest, Gregg cannot curb his curiosity to check out the future - so he crawls through the hole to future, to eventually find to his horror that...

See also.

1. Robert Heinlein's "By His Bootstraps" & Ted Chiang's "Merchant & Alchemist's Gate" (download text/MP3) both feature time travel gadgets similar to that in this story.

Fact sheet.

First published: Astounding, March 1943.
Download full text.
Rating: B.
Among the stories from John Campbell's Astounding/Analog.
Related: Stories of Henry Kuttner, C L Moore (as by Lewis Padgett); fiction from 1940s.