Susan Ertz was born in Walton-on-Thames, England, to American parents. The family moved back and forth between the two countries during her childhood, but Susan decided to live in England when she was 18. In 1932, she married John Ronald McCrindle, a British Army officer.
She wrote about 20 novels beginning with Madame Claire in 1923, many of them with a female lead character who is trying to understand a hostile world. One of her best known books was The Proselyte (1933), which concerned an Englishwoman who married a Mormon missionary and moved to Utah with him. Her science fiction novel Woman Alive (1935) was a story of the aftermath of a war and plague set in 1985. Her book In the Cool of the Day (1960), was adapted into a 1963 film of the same name. She is probably most famous today for a quote from her novel Anger in the Sky (1943): "Millions long for immortality who don't know what to do with themselves on a rainy Sunday afternoon."