The technologies which have had the most profound effects on human life are usually simple.

The PhD system is the real root of the evil of academic snobbery. People who have PhDs consider themselves a priesthood, and inventors generally don't have PhDs.

It is in the long run essential to the growth of any new and high civilization that small groups of men can escape from their neighbors and from their government, to go and live as they please in the wilderness. A truly isolated, small, and creative society will never again be possible on this planet.

Aviation is the branch of engineering that is least forgiving of mistakes.

There are three reasons, . . . apart from scientific considerations, mankind needs to travel in space. The first . . . is garbage disposal; we need to transfer industrial processes into space so that the earth may remain a green and pleasant place for our grandchildren to live in. The second . . . to escape material impoverishment: the resources of this planet are finite, and we shall not forego forever the abundance of solar energy and minerals and living space that are spread out all around us. The third . . . our spiritual need for an open frontier.

The great advances in science usually result from new tools rather than from new doctrines.

Science is my territory, but science fiction is the landscape of my dreams.