One of the major problems encountered in time travel is not that of accidentally becoming your own father or mother. There is no problem involved in becoming your own father or mother that a broadminded and well-adjusted family can't cope with.

I'm up to here with cool, okay? I am so amazingly cool you could keep a side of meat in me for a month. I am so hip I have difficulty seeing over my pelvis.

If they don’t keep exercising their lips, he thought, their brains start working.

Solutions nearly always come from the direction you least expect, which means there's no point trying to look in that direction because it won't be coming from there.

The first ten million years were the worst," said Marvin, "and the second ten million years, they were the worst too. The third ten million years I didn't enjoy at all. After that I went into a bit of a decline.

In the old days, writers used to sit in front of a typewriter and stare out of the window. Nowadays, because of the marvels of convergent technology, the thing you type on and the window you stare out of are now the same thing.

‎If you ever find you need help again, you know, if you're in trouble, need a hand out of a corner..." "Yeah?" "Please don't hesitate to get lost.