You travel life has the aspect of a dream. It is something outside the normal, yet you are in it. It is peopled with characters you have never seen before and in all probability will never see again. It brings occasional homesickness, and loneliness, and pangs of longing ... But you are like the Vikings who have gone into a world of adventure, and home is not home until you return.

I am not mad. I am eccentric perhaps--at least certain people say so; but as regards my profession. I am very much as one says, 'all there.

Vous eprouves trop d'emotion, Hastings, It affects your hands and your wits. Is that a way to fold a coat? And regard what you have done to my pyjamas. If the hairwash breaks what will befall them?' 'Good heavens, Poirot,' I cried, 'this is a matter of life and death. What does it matter what happens to our clothes?' 'You have no sense of proportion Hastings. We cannot catch a train earlier than the time that it leaves, and to ruin one's clothes will not be the least helpful in preventing a murder.

You cannot mix up sentiment and reason.

To rush into explanations is always a sign of weakness.

With method and logic one can accomplish anything.

Intuition is like reading a word without having to spell it out. A child can't do that because it has had so little experience. A grown-up person knows the word because they've seen it often before.