Cynthia Jebb, Lady Gladwyn (née Noble) was born to an aristocratic family, a daughter of Sir Saxton Noble and his wife Lady Celia Brunel. She was a great-granddaughter of Isambard Kingdom Brunel, one of the key figures of the British Industrial Revolution. In 1929, she married Gladwyn Jebb, a diplomat who served as British Ambassador to France from 1954 to 1960. In 1960, her husband was given a peerage as the 1st Baron Gladwyn and Cynthia became known as Lady Gladwyn. She was a noted hostess of Liberal and London politics and kept a diary in which she recorded personal opinions about the people she met, among them Ernest Bevin, Anthony Eden, Harold Macmillan, Lady Diana Cooper, and Nancy Mitford. It was published by her son in 1995.