Our weapon is our knowledge. But remember, it may be a knowledge we may not know that we possess.

I have enjoyed greatly the second blooming that comes when you finish the life of the emotions and of personal relations; and suddenly find - at the age of fifty, say - that a whole new life has opened before you, filled with things you can think about, study, or read about...It is as if a fresh sap of ideas and thoughts was rising in you.

Unless you are good at guessing, it is not much use being a detective.

Who are you? You don't belong to the police?' 'I am better than the police,' said Poirot. He said it without conscious arrogance. It was, to him, a simple statement of fact.

Nobody believes in magicians any more, nobody believes that anyone can come along and wave a wand and turn you into a frog. But if you read in the paper that by injecting certain glands scientists can alter your vital tissues and you'll develop froglike characteristics, well, everybody would believe that.

It is deplorable...to remove all the romance - all the mystery!

Don't think. That is the wrong way to bring anything back. Let it go. Sooner or later it will flash into your mind.