Teresa Peschel, author of "Agatha Christie, SheWatched" and the "International Agatha Christie, She Watched," discuss "The Secret Adversary," the 1929 German silent movie. This movie set the pattern for future Christie adaptations, for good and otherwise.

Joining Teresa is her husband, technical adviser, and straight man, Bill Peschel. Together, they are Peschel Press, publisher of intriguing, intelligent, and idiosyncratic books.