Inspector Richard Queen wanted to know the identity of the murdered man. How could he solve a murder mystery without knowing who was murdered? The body was found in a private room of the Hotel Chancellor; no one connected with the investigation had ever seen the man before. His name, where he came from, why he was there, remain a mystery to the end. Yet all who were enmeshed in the web of the tragedy found their lives changed by the death of the nameless nobody.
But even more baffling was the amazing scene of the crime. Everything had been turned backwards: the victim's clothing had been turned backwards, the rug was upside down, the pictures were facing the wall. And what was the explanation of the ramrods stuck up the victim's back?

"The Chinese Orange Mystery (1934) has one of EQ's most baroque and inventive puzzles. It is none too realistic, and the storytelling sags badly between the murder and its solution, but its finale shows the tremendous imagination of the Golden Age mystery tale. It is similar to The Dutch Shoe Mystery in that it depends on a floor plan, but is even better as a complex plot. In some ways, it is the fulfillment of the promise of that early novel, one that blossoms out into full-fledged surrealism and splendor. Both books seem Chestertonian. Maybe this book is the most John Dickson Carr like of Queen's novels, and it is regarded as an experiment by its author in writing a "John Dickson Carr book". However, a comparison of the dates suggests that it was written before Carr became "himself", and if there were influence here it would be in the other direction. The technique of the book is closely related to the "impossible crime", although EQ does not actually use it to create an impossible crime situation in the novel. Despite this, many historians of the locked room story seem to (falsely) remember it as a "locked room" book; it appeared on the poll of the top ten impossible crime books, for example, conducted by Edward D. Hoch for the Mystery Writers of America. This false memory is a remarkable case of collective amnesia. On a deeper level, the mystery writers who told Hoch that it was one of their favorite locked room stories were essentially right: it does come straight out of the impossible crime tradition. (Michael E.Grost)

The nurse is named Diversey ; one wonders if this is in homage to MacKinlay Kantor's first novel, Diversey (1928). Hammett is also mentioned by name in this book. The suspects named Macgowan (with a small g) could be a  reference to Kenneth Macgowan (as in The Origin of Evil), who edited the anthology Sleuths (1931)." (Michael E.Grost)
In 'The Hollow Man' Anthony Boucher put a reference to the master concerning the 'Chinese Orange Mystery' that "Ellery Queen has shown us still another method [of tampering with bolts], entailing the use of the dead man himself -- but a bald statement of this, taken out of its context, would sound so wild as to be unfair to that brilliant gentleman."

Ellery again with pince-nez, bachelor who has his own view on marriage. He smokes cigarettes and uses an wooden stick. No mention of the Duesenberg.
Richard studied in Heidelberg, he used to be captain in an outside N.Y. district. He solved a case in 41 St. where cocaine-pusher Dippy Mc Guire got a bullet in the belly.
Djuna and Dr.Prouty (with a cigar) reappear. The NYPD is represented by Ritter, Hesse, Pigott, Johnson and sergeant Velie.
The story is set during one week in N.Y. where Donald Kirk is beaten to death in the Chancellor hotel.
There is a challenge for the reader present and in it Ellery apologizes about having nearly forgotten a challenge to the reader in the last book and to have 'forgotten' it in the previous book as well. (There was no challenge in The Siamese Twin Mystery)