Marilyn Livingstone and Morgen Witzel; an Anglo-Canadian wife-husband team of writers who used the pen name A. J. MacKenzie. They have written more than twenty non-fiction books under their own name. Two of their interesting series of crime thrillers are- "The Simon Merrivale Mysteries" and "Hardcastle & Chaytor Mysteries". Their legacy as A. J. MacKenzie endures, weaving historical mysteries that amuse readers across time and place.