The first-ever Agatha Christie adaptation became a real-life mystery

Agatha Christie has been adapted for film and television for nearly 100 years and is widely cited as the best-selling novelist of all time. Her very first adaptation became surrounded by real-life mystery that continues to intrigue. Her popularity endures half a century after her death, as evidenced by the recent Kenneth Branagh-led Hercule Poirot films including Murder on the Orient Express.