Mary Borden was born into a wealthy Chicago family. She attended Vassar College, graduating with a B.A. in 1907. In 1908 she married George Douglas Turner, with whom she had three daughters; Joyce (born 1909), Comfort (born 1910) and Mary (born 1915). She was living in England in 1914 at the outbreak of the war and used her own money to equip and staff a field hospital close to the Front in which she herself served as a nurse from 1914 until the end of the war. It was there she met Brigadier General Edward Louis Spears, whom she re-married in 1918 following the dissolution of her marriage to George Douglas Turner. Despite her considerable social commitments as the wife of a prominent diplomat, she continued a successful career as a writer. During her war-time experience she wrote poetry such as 'The Song of the Mud' (1917). Notably, her work includes a striking set of sketches and short stories, The Forbidden Zone (1929), which was published in the same year as A Farewell to Arms, Good-Bye to All That and All Quiet on the Western Front. Even in this context, contemporary readers were disturbed at the graphic, sometimes hallucinatory, quality of this work coming from a woman's pen.
Living in England between the wars, she was drawn back to France in the expectation of mounting some sort of aid facility similar to that she had run in the first war. With funds donated by Sir Robert Hadfield via his wife, Lady Hadfield, she set up the Hadfield-Spears Ambulance Unit, which was based in Lorraine until forced by the German Blitzkrieg to retreat across France before its evacuation from Arcachon in June 1940. In Britain, the unit re-grouped and received further funding from the British War Relief Society in New York. In May 1941, the Hadfield-Spears Ambulance Unit was attached to the Free French in the Middle East, before accompanying their forces across North Africa, Italy and France. Journey Down a Blind Alley, published on her return to Paris in 1946, records the history of the unit and her disillusion with the French failure to put up an effective resistance to the German invasion and occupation.
A first person account of Lady Spears and the Hadfield-Spears Ambulance Unit can be found in To War with Whitacker, The Wartime Diaries of the Countess of Ranfurly 1939-45. ISBN 0 7493 1954 2