Ellery Queen is a pseudonym used by two American cousins, Frederic Dannay and Manfred B. Lee, who wrote detective fiction. They are considered to be one of the most important and influential writers in the mystery genre. They created the fictional detective Ellery Queen, who appeared in more than 30 novels and several short stories. The Ellery Queen mysteries often featured complex puzzles and intricate plots. The cousins also edited several anthologies of mystery stories and established the Ellery Queen Mystery Magazine.