Cavin was born Ruth Brodie in Pittsburgh, Pennsylvania to Jewish immigrants who taught her how to read as a young child.
[2] She attended Carnegie Institute of Technology, earning her undergraduate degree there in 1939 and married Bram Cavin, a journalist with BusinessWeek whom she met after moving to New York City.
[3] Hired by St. Martin's Press to work at its Thomas Dunne Books unit when she was already in her 70s, Cavin helped develop first novels by such mystery fiction authors as Donna Andrews, Steve Hamilton, Julia Spencer-Fleming and Laurie R.
[3] The Malice Domestic Contest, a yearly competition honoring best first mystery novels, was begun by St. Martin's Press based on Cavin's suggestion.
[4] She helped edit and publish 900 books in a broad range of genres during her tenure there, continuing to work as an editor until 2010 when she was diagnosed with lung cancer.