"Oh, I'm an incredible sausage machine," the late mystery writer Agatha Christie once jokingly claimed, speaking of her prolific output of novels, stories, and plays. Christie's many works sold well over 400 million copies--a record topped only by the Bible and William Shakespeare--and were translated into 103 languages. Her play "The Mousetrap," originally written as a birthday gift for Queen Mary, is the longest running play in theatrical history. These staggering statistics testify to the enduring popularity of Christie's work.

Writing in the Dictionary of Literary Biography, H. R. F. Keating claimed that "Christie is a towering figure in the history of crime literature for two reasons. First, she consolidated the form of the pure mystery novel, achieving in five or six of her books puzzle stories that set a standard unlikely ever to be decisively bettered. Second, she sold more books than any other writer except Shakespeare.... She was...