Marie Adelaide Belloc Lowndes (1868–1947) was a prolific English writer and biographer, best known for her psychological suspense novels. The sister of writer Hilaire Belloc, she grew up in a literary environment that influenced her career. Her fame rests mainly on the novel *The Lodger* (1913), a thriller based on the Jack the Ripper murders, told from the perspective of a couple who suspects their lodger. This work is considered a classic of the genre and a precursor to the modern psychological thriller. Its success led to numerous adaptations, the most famous of which is Alfred Hitchcock's silent film *The Lodger: A Story of the London Fog* (1927), which solidified the novel's international reputation. Throughout her career, Belloc Lowndes published over forty novels, biographies, and short story collections, establishing herself as one of the most popular authors of her time in the field of mystery and suspense literature.