This experience deepened her understanding and love of children through the way they responded to the books, and was foundational to her later career as an editor teaching her to always keep in mind the end reader in the process.
While she enjoyed this work, she accepted the tempting offer to become editor of Booklist forcing her to move back to Chicago in 1913.
[3][4][5] At the 1920 American Library Association (ALA) Conference in Colorado Springs, she reported that she would be working with Mabel Williams, a librarian at the New York Public Library (NYPL), to edit and grade approximately 600 children's books, titles concerning children for teachers, and expressed the need for a high-quality list of high school level books.
She protested his involvement and after resigning on the spot, she was assured the sales manager would not undermine her work and she moved to New York.
[3][4][6][5] In 1932, Massee was fired from Doubleday and Viking Press jumped at the opportunity to hire her to found their new children’s book department in 1933.
However, she continued working with Viking Press as an advisory editor until her death from a stroke at her home in New York City on December 24, 1966.
Critics acknowledged Massee’s ability regarding text, design, and illustration as well as her endorsement of new methods of production such as offset lithography.
Frances Clarke Sayers wrote of Massee, "She not only responds to creative work when it is completed but she senses the hidden possibilities in the writers and artists themselves."
It was formed by colleagues and friends of Massee, including Margaret Lesser Foster, Robert McCloskey, and Elizabeth Gray Vining, in 1967 and donated to what is now Emporia State University in 1972.