Sophie Adelaide Radford de Meissner (November 17, 1854 – April 17, 1957) was an American author, playwright, diplomat's wife, spiritualist and socialite.

Sophie was born third of seven children to William Radford (September 9, 1809 – January 8, 1890), an officer in the United States Navy, and Mary "Minnie" Elizabeth Lovell (April 12, 1829 – October 27, 1903).

[2]: 210–212  At the close of the American Civil War, the Radfords moved to Washington, D.C. Sophie attended Madam Burr's School near Fourteenth Street and New York Avenue where the language was French only, regardless of the subject.

As Radford performed his naval duties in the Mediterranean Sea and European west coast, his family sailed with him to Spain, Portugal, Algiers, France, the Netherlands, and Italy.

A month after the outbreak of the Franco-Prussian War, her father relinquished his command and went to Lausanne to retrieve his children believing any battles would be distant.

They married November 20, 1877 in two ceremonies: first at the Episcopal Church and then at the Radford residence on 1736 (now 1734) N Street NW in the DuPont Circle neighborhood.

Sacha was educated in a military college in Russia and rose to the rank of cornet in the 44th Regiment of Dragoons of the Imperial Russian Army.

Sophie moved back to Saint Petersburg to be near her son, accepting a position as lady-in-waiting to another widow, the dowager Empress of Russia, Maria Feodorovna.

[10]: 102–112 [11] Two other victims of the Titanic sinking and also associated with Taft, William Thomas Stead (also a spiritualist) and Francis Davis Millet are said to have communicated with Sophie.