The French Powder Mystery is a spell-binding tale of crime, intrigue, and extraordinary detection. At crowded noon, in front of Fifth Avenue's most fashionable department store, while hundreds of sidewalk onlookers watch a demonstration of modernistic furniture in the window, the demonstrator touches a button regulating a concealed wall-bed--the bed swings out of the wall--and from its dark recesses tumbles the distorted, crumpled corpse of a beautiful woman....

Ellery Queen moves vitally and refreshingly through his own story -- a slender, cynical young man with a genius for piercing the veil of commonplaces and arriving at foolproof conclusions. Old Inspector Queen, his father, again takes you through the complicated process of a police investigation, although it is Ellery who is responsible for the solution of one of the most stimulating and baffling detective stories ever written. And the denouement is surprising and yet inevitable.(Cover)

"A brilliant, thrilling, ingenious story." -- William Lyon Phelps
"The logical successor to Sherlock Holmes." -- London Times
"Ellery Queen belongs with Sherlock Holmes, Arsene Lupin, Philo Vance, and other master-minds. -- William Lyon Phelps

The fact that this title went through seven impressions, three before publication, before being handed over to the reprinters is some indication of how big a splash Ellery made-and how quickly. The dustjackets of the first prints are extremely elusive, and a high four figure item. "The French Powder Mystery (1930), like its successor, contains a strong initial investigation. It takes up 25 chapters, or the first two thirds of the book, and shows EQ's astonishing skills at constructing a detective story plot. The crime and the events surrounding it develop into ever more complex and logical patterns; Ellery moves through several stages of deduction, each leading to a deeper understanding of the crime itself. The story has considerable beauty; the inquiry about the keys, or the timetables involved show EQ's ability to create fascinating patterns of plot. EQ likes boundaries involving space, time and knowledge. He is fascinated with rooms that have not been entered, lines that have not been crossed, apartments that have been guarded and watched. He is also concerned with who knew things and didn't know things, which in turn often depends on who has participated in events and who hasn't. These become boundary markers in the complex logical geometry of his plots. The limitations of the novel, and its reason for still classifying it as a journeyman work, deal with the solution. Later EQ novels will often have the most startling surprises in their solutions; this book runs out of steam two thirds of the way through, and its solution adds only a single new clue, together with the identity of the murderer. Although logical and fair, not the deeply creative finales of the great EQ books. EQ, as is his wont, has given partial solutions to the crime at several stages in the book, so the reader gets a full mead of deduction and revelation in the novel which leaves almost nothing for the finale."(Michael E.Grost)

We get to know Ellery, again with walkingstick, a thin silver watch and pince-nez (which isn't exactly the same as a lorgnet), in a much more physical way. He is described as a tall athletic man with the suggestion of force, looked very intelligent around the forehead had long fingers and cool stiff lips. He looked thirty but was actually younger. His clothes came from Bond street. Several references to other cases: The arrest of Don Dickey, an American jewelthief in Berlin for which the mayor gave him a special aluminum tool for research as award. In the Kingsley Arms murder, O'Shaughnessy had killed Herrin, which was proven by lifting his fingerprints from dead man's shoe.
Ellery also got an idea for a short-story by reading something about 'the Retreat of the 10000 in the Old Armenia.' the sandals these man wore during sleep were frozen to the ground.
Richard Queen again handles the old brown snuffbox and is involved in the case of Pete Slavin's gang.
The 'monkeylike' Djuna, Hagstrom (who performs steno!), Hesse, Flint, Ritter, Johnson, Pigott and Velie reappear. As do Dr.Prouty, Henry Sampson (involved in the White Test Case) and the redheaded Timothy Cronin.
The story again takes place in N.Y. at the French warehouse on the corner of  39nd street and Fifth Avenue.
Winifred March gets murdered with a French colt .38

"The furniture in The French Powder Mystery is probably Art Deco, although it is never called by that name in the novel. EQ calls it "modernist", and gives a vivid and accurate description of how it was viewed by its contemporaries, both artistically and sociologically. Considering the tremendous enthusiasm today for preserving America's great Art Deco heritage, with Deco societies springing up in every city, this book should be better known. EQ was deeply interested in the world around him. His books form a record of an important era in American life."(Michael E.Grost)
In chapter 22 some of the great adventure (and sometimes mystery) writers of an earlier generation (Doyle, Jack London, Robert W. Chambers, George Barr McCutcheon, Richard Harding Davis) are mentioned.

The challenge to the reader is included, as is the map and the list of characters.