Ellery Queen is a pseudonym used by two cousins, Frederick Dannay and Manfred B. Lee to write detective fiction. Some of the later Ellery Queen novels were ghost-written by Theodore Sturgeon, Jack Vance, and other prominent writers.
In their successful series of novels, Ellery Queen is not only the name of the author, but also the detective-hero of the stories. The writing team also wrote four novels under the name of Barnaby Ross about a Shakespearian actor/detective named Drury Lane. These novels were later reiussed under the Ellery Queen byline.
For a while in the 1930s "Ellery Queen" and "Barnaby Ross" staged a series of public debates in which one cousin impersonated Queen and the other impersonated Ross.
The early Queen novels encouraged the reader to attempt to solve the puzzle, with an explicit note in the text when the reader had all the necessary information.
There were many paperback novels written by "Ellery Queen" in the 1960s that did not feature the detective Ellery Queen. For instance, three novels featuring the governor's "troubleshooter" Mike McCall -- The Campus Murders (1969, written by Gil Brewer); The Black Hearts Murder (1970, written by Richard Deming); and The Blue Movie Murders (1972, written by Edward D. Hoch) -- were published under the "Ellery Queen" byline. Jack Vance also wrote four of these books.