“Can one build an honest house on dishonest foundation? I do not know. But I do know that I want to try. (Edward Ferrier)”

“I know there's a proverb which that says 'To err is human,' but a human error is nothing to what a computer can do if it tries.”

“What I feel is that if one has got to have a murder actually happening in one's house, one might as well enjoy it, if you know what I mean.”

“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.”

“Liking is more important than loving. It lasts. I want what is between us to last, Luke. I don't want us just to love each other and marry and get tired of each other and then want to marry some one else.""Oh! my dear Love, I know. You want reality. So do I. What's between us will last for ever because it's founded on reality.”

“You do think you know about everything," said her husband. I do," said Tuppence.”

“A great many men are mad, and no one knows it. They do not know it themselves”