The Mitford Murders by Jessica Fellowes (Sphere, £12.99)
To this day, the crime remains unsolved. But Fellowes, author of the Downton Abbey companion books, has taken the bones of this real-life mystery and fashioned her own solution.
Louisa Cannon, 18, escapes the clutches of her abusive uncle by securing a post as nursemaid to the Mitford family in Oxfordshire.
Having travelled the same train route as the unfortunate Miss Shore, she and 16-year-old Nancy Mitford become embroiled in the search for her killer.
Marking the start of a new series, this is a gentle, old-fashioned novel rich in period detail and nostalgia, its plot containing enough misunderstandings and false leads to overcome the moments when credulity is overstretched.