Speech ... is an invention of man's to prevent him from thinking.

Any coincidencce is worth noticing. You can throw it away later if it is only a coincidence.

Many years ago, when I was once saying sadly to Max it was a pity I couldn't have taken up archaeology when I was a girl, so as to be more knowledgeable on the subject, he said, 'Don't you realize that at this moment you know more about prehistoric pottery than any woman in England?'

Time does not dispose of a question - it only presents it anew in a different guise.

There are more important things than finding the murderer. And justice is a fine word, but it is sometimes difficult to say exactly what one means by it. In my opinion, the important thing is to clear the innocent. - Hercule Poirot

If you confront anyone who has lied with the truth, he will usually admit it - often out of sheer surprise. It is only necessary to guess right to produce your effect.

To every problem, there is a most simple solution.