A.J. Mackenzie is the pseudonym of Marilyn Livingstone and Morgen Witzel, a husband-and-wife team of writers and historians. Morgen has an MA in renaissance diplomacy, and Marilyn has a PhD in medieval economic history. They have written two books of medieval history and several novels, including the Simon Merrivale Mysteries, set in medieval Europe. Marilyn Livingstone was diagnosed with cancer in 2022 and passed away in September 2023.
