About Agatha . . . An MBR Extra by John Dwaine McKenna    The year 2020 will mark the 100th anniversary of the first novel of the most widely-read author in all the world.  Her name is Agatha Christie.  Her first detective novel, The Mysterious Affair at Styles, debuted on Nov 6, 1920. In honor of this iconic and beloved author, the MBR is highlighting some facts about her