Bargainnier, Earl F. The Gentle Art of Murder: The Detective Fiction of Agatha Christie. Bowling Green, Ohio: Bowling Green University Popular Press, 1980.
Barnard, Robert. A Talent to Deceive: An Appreciation of Agatha Christie. New York: Dodd, Mead, 1980.
Fitzgibbon, Russell H. The Agatha Christie Companion. Bowling Green, Ohio: Bowling Green State University Popular Press, 1980.
Light, Alison. Forever England: Femininity, Literature, and Conservatism Between the Wars. New York: Routledge, 1991.
Rowland, Susan. From Agatha Christie to Ruth Rendell: British Women Writers in Detective and Crime Fiction. New York: Palgrave, 2001.
Wagoner, Mary. Agatha Christie . Boston: Twayne Publishers, 1986.
Authors set a tone in literature by conveying emotions/feelings through words. The way a person feels about an idea/concept, event, or another person can be quickly determined through facial expressions, gestures and in the tone of voice used. In literature an author sets the tone through words. The possible tones are bounded only by the number of possible emotions a human being can have.
Protagonist-the leading character, hero, or heroine of a drama or other literary work.