Although Castle Warlock is not technically a “sequel” to Mary Marston, thematically, the two books are very much linked. In the former, MacDonald explores the depth of the father-son relationship, while in the latter, he examines the father-daughter relationship.
Neither of Castle Warlock's main characters (Mary and Cosmo) have a living mother, thus further accentuating those relationships and raising them to their ideal. In this novel, MacDonald once again returns to the highlands of Scotland, setting his story in the hills south of Huntly. In it we encounter some of his most vivid descriptions of that wild terrain, including snowstorms, the joys of summer, harvests, etc.
Along with What’s Mine’s Mine, Castle Warlock is one of the most thoroughly Scottish of all MacDonald’s novels, and is a favorite among readers for its spiritual, relational, and natural splendor.
[Original Print: 1882, Sampson Low & Co.]