The fish that first ventured ashore had considerable practical problems.

In my considered opinion, the profit to be made by permanent settlement in space is nothing less than the survival of industrial civilization, and therefore the survival of nearly the entire human race, along with such amenities as peace, freedom, enough to eat, and the chance to reach a high age in good health.

A fanatic's willingness to kill or be killed in the service of a cause cannot prove the rightness of that cause.

A fanatic is a man who, when he's lost sight of his purpose, redoubles his effort.

Let us settle down to the serious business of getting drunk.

The single definition of government I've ever seen that makes sense is that it's the organization which claims the right to kill people who won't do what it wants.

What five books would I like to be remembered for? Well... Tau Zero, I like that one especially. It was somewhat of a tour de force, and I think it got across what I was trying for.