You have a tendency, Hastings, to prefer the least likely. That, no doubt, is from reading too many detective stories.

I've always believed in writing without a collaborator, because where two people are writing the same book, each believes he gets all the worry and only half the royalties.

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

Any medical man who predicts exactly when a patient will die, or exactly how long he will live, is bound to make a fool of himself. The human factor is always incalculable. The weak have often unexpected powers of resistance, the strong sometimes succumb.

You are the patient one, Mademoiselle,' said Poirot to Miss Debenham. She shrugged her shoulders slightly. 'What else can one do?' You are a philosopher, Mademoiselle.' That implies a detached attitude. I think my attitude is more selfish. I have learned to save myself useless emotion.

Never worry about what you say to a man. They're so conceited that they never believe you mean it if it's unflattering.

But I know human nature, my friend, and I tell you that, suddenly confronted with the possibility of being tried for murder, the most innocent person will lose his head and do the most absurd things.