She studied at McGill University in Montreal, earning a Bachelor of Science degree in 1950.
She continued to live in Montreal with her husband, John N. Mappin.
From 1974 to 2005, Mappin operated the Double Hook bookstore in Montreal, which sold only Canadian books.
[2] She also served on the jury for the 1999 Giller Prize for Canadian fiction.
The Global and Mail and others have called Mappin a 'heroine of Canadian literature' for her pioneering efforts in the field.