Best-selling author Agatha Christie published her first novel, The Mysterious Affair at Styles, in 1920, and went on to become one of the most famous writers in history, with mysteries like Murder at the Vicarage, Partners in Crime and Sad Cypress. She sold billions of copies of her work and was also a noted playwright and romance author. The youngest of three siblings, she was educated at home by her mother, who encouraged her daughter to write.