Ruth Inglis, née Langdon, was born in Mukden, Manchuria, China, the daughter of William Russell Langdon, a U.S. diplomat and Japanese scholar, and his wife Laura Filer, later a noted Asian art dealer. She grew up speaking Chinese and graduated from Barnard College in New York in 1949. She then went back to Asia to rejoin her parents, who had been posted to Singapore, and began her career as a journalist with The Straits Times. She later moved to Paris to work for the Continental Daily Mail.
In 1952, she married Keith Woodeson, a British artist, with whom she had a daughter, and they moved to the USA. She joined the public relations staff at Sarah Lawrence College in Bronxville, NY. In 1957, after a divorce from Woodeson, she went to London. There she married Brian Inglis, a journalist and historian, and had a second child. Her husband became editor of the Spectator in 1960 and she contributed to its "Consuming Interest" column under the pseudonym Leslie Adrian. She also hosted soirées at their home that brought together leading literary, artistic, and political figures of the 1960s. She went to work for Nova magazine and The Observer, profiling personalities and writing about controversial issues. She published her first book, A Time to Learn, in 1973. The following year, she and Inglis divorced, and she became a feature writer for the Daily Express.
Other books included Sins of the Fathers (1978), Must Divorce Hurt the Children? (1982), The Good Step-Parents' Guide (1986), and The Children's War (1989), an account of the experiences of young evacuees in World War II, which was accompanied by an exhibition at the Imperial War Museum.