The novel "Mary Marston" is considered a realistic and psychological novel by MacDonald, focusing on the inner lives and moral struggles of its characters. It delves into themes of human relationships, personal growth, and moral development.The story revolves around its protagonist, Mary Marston, exploring her life, experiences, and relationships within a Victorian setting. MacDonald's works often emphasize moral and spiritual growth, depicting characters' internal struggles and their pursuit of virtue and goodness."Mary Marston" showcases MacDonald's emphasis on the inner lives of his characters, offering a thoughtful exploration of human nature, ethical choices, and the complexities of interpersonal relationships within the context of Victorian society.