The Queen of Mystery has come to Harper Collins! Agatha Christie, the acknowledged mistress of suspense—creator of indomitable sleuth Miss Marple, meticulous Belgian detective Hercule Poirot, and so many other unforgettable characters—brings her entire oeuvre of ingenious whodunits, locked room mysteries, and perplexing puzzles to William Morrow Paperbacks. Set during the dark days of World War Two, Christie’s N or M? puts two most unlikely espionage agents, Tommy and Tuppence Beresford, on the trail of a pair of Nazi spies who have murdered Britain’s top agent.