Of such things, petty annoyance and aimless thrusts, is history made.

Success has its own inertia.

Most of the visible signs of aging are the result of the inexorable victory of gravity over tissue—the sagging of the cheek and the drooping of the breast. With the Moon's gravity one-sixth that of Earth, it isn't really hard to understand that people will stay young-looking.

Great and possibly dangerous efforts have been abandoned because the danger was feared more than greatness was desired.

The more complicated and silly any plot, the more rickety it is and the more anxious the plotter.

The gravity is weaker on the Moon than on the Earth, so you press against the ground much less strongly, and that means there is much less friction. Everything is more slippery on the Moon than on the Earth. That's why the floors in our corridors and apartments seemed unfinished to you.

The easiest way to solve a problem is to deny it exists.

You don't beat refusal to believe in a frontal attack.

"It's rather disillusioning. Does everyone just believe what he wants to?"

"As long as possible. Sometimes longer."

There are no happy endings in history, only crisis points that pass.

You don't beat refusal to convert in a frontal attack.

Scientists who write about science fiction seldom write about the areas in which they do their science, almost as if knowing too much about a subject limits a writer's imagination.