Margery Allingham (edit name/settings)

Margery Allingham was an English crime writer, best remembered for her detective stories featuring gentleman sleuth Albert Campion.

Her first novel, Blackkerchief Dick, was published in 1923 when she was 19. While Blackkerchief Dick was well received, it was not a financial success. She also wrote several plays and attempted to write a serious novel, but finding her themes clashed with her natural light-heartedness, she decided instead to try the mystery genre. Her first work of detective fiction was a serialized story published by the Daily Express in 1927. Entitled The White Cottage Mystery, it contained atypical themes for a woman writer of the era.

Her breakthrough occurred in 1929 with the publication of The Crime at Black Dudley. This introduced Albert Campion, albeit originally as a minor character. Allingham also wrote under the pseudonym Maxwell March.

Source: Wikipedia