"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."

"I sometimes wonder if I am a woman at all. I am so unfeminine."

"There's nothing so comfortable as a good, old-fashioned murder."

"It is my experience that no one, in the course of conversation, can fail to give themselves away sooner or later. Everyone has an irresistible urge to talk about themselves."

"If you are to be Hercule Poirot, you must think of everything."