Butterflies are not insects,' Captain John Sterling said soberly. 'They are self-propelled flowers.
A slave cannot be freed, save he do it himself. Nor can you enslave a free man; the very most you can do is kill him!
Audacity, always audacity - soundest principal of strategy.
Spacemen die if they stay in one place.
Women will forgive anything. Otherwise, the race would have died out long ago.
A handy short definition of almost all science fiction might read: realistic speculation about possible future events, based solidly on adequate knowledge of the real world, past and present, and on a thorough understanding of the nature and significance of the scientific method.