She was an adopted child, raised in Illinois. She worked in Chicago in advertising as a research librarian and as an editor of The Merchandiser, prior to taking up fiction writing. She was married to Harry Davis, the character actor, from 1946 until his death in 1993. She published many novels and short stories. Among them are two sets of series novels, but she mainly wrote stand alone novels. Her novels explore psychological suspense, as was popular for many decades, and has ‘an especially strong way of sharing with readers the minds of female characters confronting hazards and crisis’. She was nominated for an Edgar Award eight times, served as President of the Mystery Writers of America in 1956 and was declared a Grand Master by that organization in 1985.
She was on the initial steering committee of Sisters in Crime when it was formed in 1986 and her support was influential in dampening attacks on the new organization.