"Imagination is a good servant, and a bad master."

"The best revenge is massive success."

"Crime is terribly revealing. Try and vary your methods as you will, your tastes, your habits, your attitude of mind, and your soul is revealed by your actions."

"I have always believed to write a good detective story, you must know all about detective stories."

"Instinct is a marvelous thing. It can neither be explained nor ignored."