Deborah Harkness, author of A Discovery of Witches, wrote most of the aforementioned novel in first person, but also included sections written in third person, focusing primarily on secondary character, Matthew Clairmont. In the Q&A section of her website, Harkness gives this response when asked why she combined the two methods: "Early in the process of writing the book I realized that vampires must be secretive and protective creatures. For Matthew, this means he has both a strong instinct to hide from Diana’s questions and a need to protect her from threats. The only way to show that dynamic in Matthew (without making the reader very impatient with him) was to take Diana out of the picture temporarily and show him interacting with others who knew him in other ways. Since Diana is the first-person narrator, this caused some problems that omniscient narration solved. I think the combination of the two narratives works surprisingly well and gives the reader the immediacy of Diana’s experience along with some answers to their questions about Matthew."
As a reader, I found the combination jarring and unnecessary. I like suspense. I would have preferred to wonder more about Matthew's motivations and to worry whether Diana was unwise to trust him. For me, sticking only with the first person point of view would have added a tantalizing layer to the story. Every time the point of view changed, I was pulled out of the plot, and portions of the story seemed repetitive after experiencing them from both points of view. I wonder how the novel would have flowed if Harkness had used only omniscient point of view, balancing the story among the two characters and abandoning first person altogether.