In addition to writing popular children's stories, she ran her husband Daniel Lothrop's publishing company after his death.

Harriett Mulford Stone was born in New Haven, Connecticut, in 1844.The daughter of New Haven architect Sidney Mason Stone, she was “brought up in an atmosphere of culture and learning enhanced by free access to her father’s large library.”[2] From early girlhood she “delighted in creating imaginary people”.

[4] While a student there “she displayed such mental alertness, combined with retentive memory and a great imaginative and poetic talent that she was marked for future success.”[5] She traveled extensively in the United States, and began creating literary compositions early in life.

[5] She published nothing until 1878 when, at the age of 34, she began sending short stories to Wide Awake, a children's magazine in Boston.

Daniel had founded the D. Lothrop Company of Boston, who published Harriett's books under her pseudonym, Margaret Sidney.

Alongside her writing career, Stone had a deep interest in historical homes and buildings and worked hard to preserve them.

These include: In later years, Stone's daughter Margaret Lothrop championed to have her childhood home, The Wayside, declared a National Historic Landmark.