He never gave up his search for the Door into Summer.

One could write a history of science in reverse by assembling the solemn pronouncements of highest authority about what could not be done and could never happen.

How can you argue with a woman who won't?

One man's 'magic' is another man's engineering. 'Supernatural' is a null word.

Heroism' often consists in keeping your head in an emergency and doing the best you can with what you have instead of panicking and being shot in the tail. People who fight this way win more battles than do intentional heroes; a glory hound often throws away the lives of his mates as well as his own.

Correct morality can only be derived from what man is — not from what do-gooders and well-meaning aunt Nellies would like him to be.

Anyone can see a forest fire. Skill lies in sniffing the first smoke.