While he lives, he must think; while he thinks, he must dream.

At two-tenths the speed of light, dust and atoms might not do significant damage even in a voyage of 40 years, but the faster you go, the worse it is--space begins to become abrasive. When you begin to approach the speed of light, hydrogen atoms become cosmic-ray particles, and they will fry the crew. ...So 60,000 kilometers per second may be the practical speed limit for space travel.

The first law of dietetics seems to be: if it tastes good, it's bad for you.

What I will be remembered for are the Foundation Trilogy and the Three Laws of Robotics. What I want to be remembered for is no one book, or no dozen books. Any single thing I have written can be paralleled or even surpassed by something someone else has done. However, my total corpus for quantity, quality and variety can be duplicated by no one else. That is what I want to be remembered for.

When I die I won't go to heaven or hell; there will just be nothingness.

If knowledge can create problems, it is not through ignorance that we can solve them.

It's the writing that teaches you.