Dame Agatha Mary Clarissa Christie, Lady Mallowan, (née Miller; 15 September 1890 – 12 January 1976) was a British author known for her 66 detective novels and 14 short story collections, particularly those revolving around fictional detectives Hercule Poirot and Miss Marple. She also wrote the world's longest-running play, the...
—Agatha Christie in A Murder Is Announced
Never tell all you know—not even to the person you know best.
—Agatha Christie in The Secret Adversary
Those are my principles, and if you don't like them... well, I have others.
Nature has no principles. She makes no distinction between good and evil.