People should be interested in books, not their authors.
Love is not everything ... It is only when we are young that we think it is.
Instinct is a marvelous thing. It can neither be explained nor ignored.
Curious things, habits. People themselves never knew they had them. [Witness for the Prosecution, also published in The Hound of Death and Other Stories.]
There's nothing so dangerous for anyone who has something to hide as conversation.
There is no detective in England equal to a spinster lady of uncertain age with plenty of time on her hands.