A Curate's Promise  is published in 1921 and she dies two years later. This last publication continues to focus on the Salvation Army and their efforts to help the urban poor. Harkness, who often published under the name Law, finishes her career with this work, showing that she remained focused on the plight of the poor.

Harkness, Margaret. A City Girl, edited Tabitha Sparks. Broadview Editions, 2017