* The Daughter of the Nile (1949): This novel tells the story of a young Roman girl who travels to Britain and becomes involved in the rebellion of Boudica.
* The Serpent and the Staff (1952): Set in Roman Britain, this novel explores the themes of love, loyalty, and betrayal.
* The Roman Road (1954): This historical novel features a young Roman soldier who is sent to Britain to help build a road.
* The Hand of Glory (1958): Set in medieval England, this book tells the story of a young woman who is accused of witchcraft.
Margaret Gagg also wrote a series of detective novels featuring the amateur sleuth, Miss Clare Mallory. These books are known for their witty prose and their focus on the darker side of English society.
Gagg's works are praised for their detailed historical accuracy and their engaging characters. She was a prolific writer and published numerous books over her lifetime.
In addition to the novels mentioned above, she also wrote short stories, essays, and articles on historical and literary subjects.