McIlwraith graduated from McGill University in 1914 and became a reader and editor for Doubleday, Page and Company.
[1] She worked as an assistant to Harry E. Maule (1886-1971), the editor of Doubleday's Short Stories magazine.
[4] Under her editorship authors and artists such as Ray Bradbury and Hannes Bok first appeared in the magazine.
As the first female editor of WT, McIlwraith's work "paved the way" for women in the field of weird and horror fiction,[6] with the perhaps predictable result that there have been wildly divergent assessments of the level of her success in this role.
[6] Retrospectively, it is clear that WT was among the most influential pulps of the 20th century, and that McIlwraith served as its editor for a substantial part of its heyday years.