The link below is to an article reporting on the death of Betty Ballantine, an important figure in the development of the modern paperback.

For more visit:
https://www.washingtonpost.com/local/obituaries/betty-ballantine-who-helped-popularize-modern-paperback-dies-at-99/2019/02/14/8ef456cc-2fdf-11e9-8ad3-9a5b113ecd3c_story.html