Behind every man now alive stand thirty ghosts, for that is the ratio by which the dead outnumber the living.

I have never grown up, but I will never stop growing.

Politicians should read science fiction, not westerns and detective stories.

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

They will have time enough, in those endless aeons, to attempt all things, and to gather all knowledge... no Gods imagined by our minds have ever possessed the powers they will command... But for all that, they may envy us, basking in the bright afterglow of Creation; for we knew the Universe when it was young.

I can never look now at the Milky Way without wondering from which of those banked clouds of stars the emissaries are coming. If you will pardon so commonplace a simile, we have set off the fire alarm and have nothing to do but to wait. I do not think we will have to wait for long.

Sometimes when I'm in a bookstore or library, I am overwhelmed by all the things that I do not know. Then I am seized by a powerful desire to read all the books, one by one.