Margaret Sidney was the pen name of American author and publisher Harriett Lothrop, best known for creating the enduring Five Little Peppers series, one of the most popular works of American children's literature of the late 19th century. Raised in a cultured and literary household in New Haven, she developed an early passion for storytelling and imaginative writing, though she did not publish until her mid-thirties. Her breakthrough came with short stories for the magazine Wide Awake, whose enthusiastic reception led to the publication of Five Little Peppers in 1881 and a long-running series that followed the Pepper family through numerous sequels. Writing under the name Margaret Sidney, she became widely read by generations of young audiences. After the death of her husband, publisher Daniel Lothrop, she successfully managed his publishing firm while raising their daughter, later returning to writing and continuing the Pepper books. Beyond literature, she played a significant role in American cultural life, helping to establish Concord, Massachusetts, as a literary center and working to preserve historic homes. She was also the founder of the Children of the American Revolution, reflecting her strong interest in history, education, and civic values.