The universe must be full of voices, calling from star to star in a myriad tongues. One day we shall join that cosmic conversation.

It will be possible in a few more years to build radio controlled rockets which can be steered into such orbits beyond the limits of the atmosphere and left to broadcast scientific information back to the Earth. A little later, manned rockets will be able to make similar flights with sufficient excess power to break the orbit and return to Earth. (1945) [Predicting communications satellites.]

Religion is a by-product of fear. For much of human history it may have been a necessary evil, but why was it more evil than necessary? Isn’t killing people in the name of god a pretty good definition of insanity?

Civilization will reach maturity only when it learns to value diversity of character and of ideas.

In accordance with the terms of the Clarke-Asimov treaty, the second-best science writer dedicates this book to the second-best science-fiction writer. [dedication to Isaac Asimov from Arthur C. Clarke in his book Report on Planet Three]

A well-stocked mind is safe from boredom.

Some things have eternal value, and compassion is one of them. I hope we never lose that. Compassion for humans as well as animals.