Mary Bonnycastle enjoyed reading the romances of British publisher Mills and Boon, and, at her urging, in 1957 Harlequin acquired the North American distribution rights to the category romance novels which had been published by Mills and Boon in the Commonwealth of Nations.
Mary Bonnycastle tyckte om att läsa kärleksromaner av den brittiske utgivaren Mills and Boon, och, på hennes enträgna begäran, förvärvade Harlequin 1957 den nordamerikanska distributionsrätten för genren kärleksromaner som hade getts ut av Mills and Boon i Samväldet.