Hi! I looking for a Bradbury tale. Is a strange one, about a little machine wich can be activate with the eyes and let you travel to infinite worlds. At the end of the story you discover that was all about "the book"
I apologized in advance for my english. I'm from Argentina
Thanks!

Welcome MJ,
I think you are referring to a portion of a science article named “The Ancient and the Ultimate” written by Dr. Isaac Asimov and originally published in “The Magazine of Fantasy and Science Fiction”, January 1973, Whole No. 260.

Part of the article discuses the new technology of the videocassette. Dr. Asimov imagines a “television cassette” that is small and easy to use. Here are some excerpts from and a summary of that portion of the article:

“…I was now going to make use of my Science Fiction expertise to look still further ahead and see how cassettes could be further improved and refined, and made still more sophisticated.”

He points out that the cassette needed a bulky piece of equipment (the video tape machine) to decode it and show the picture on a TV screen. He imagines making that equipment much smaller and placing it “within” the cassette itself.

Realizing that the cassette will use energy from the environment, he imagines one that will use “zero” energy and be “completely mobile and self-contained…does not need to be plugged into the wall…and needs no battery replacements.” It does not need an on and off switch because it can be activated by the will and “...the tape stops as soon as you remove your eye.”

He concludes by saying, “We will have it in minus five thousand years—because what I have been describing (as perhaps you have guessed) is the book!”

I feel sure that Dr. Asimov had this article republished in one of his many science books but have no idea which one it would be. I recommend getting in touch with one of his websites and asking the same question. Hopefully someone there will be able to direct you to the book it’s in.

Good luck!

Thanks! I found it!
You were right about the source.
I even found a Spanish translation of it!
I really appreciate your help!

Thanks for the acknowledgement. – Best.