(Tommy & Tuppence #3), Agatha Christie N or M? is a work of detective fiction by Agatha Christie first published in 1941. Agatha Christie also wrote romance novels under the pseudonym Mary Westmacott, and was occasionally published under the name Agatha Christie Mallowan. Find and read more books you’ll love, and keep track of the books you want to read. Goodreads members who liked N or M? (Tommy and Tuppence, #3). Readers’ questions about N or M? 2 questions answered. Be part of the world’s largest community of book lovers on Goodreads. N or M? (Tommy and Tuppence, #3) from the world’s largest community of readers. Agatha Christie is the best-selling author of all time. Find books like N or M? After the outbreak of the Second World War and many years after they worked for British intelligence, middle aged Tommy and Tuppence Beresford feel useless and sidelined. She wrote 66 crime novels and story collections, fourteen plays, and six novels under a pseudonym in Romance.