Several detective fiction writers of the 1930s set up a murder occurring during a flight over the English Channel. Freeman Wills Crofts, a retired railway engineer, depicts one here, and of course describes the passenger plane with an engineer's eye for detail: the criss-cross struts connecting the wings, the great propeller, the bus-like interior with rows of seats for forty passengers, etc. Surely a delight for nostalgia buffs! Another luminary in the "golden age" of detective fiction, Dorothy L Sayers, congratulated Freeman Wills Crofts not only on the excellence of all this, but also for attempting a new experiment in detective fiction.

The experiment was to present detection in reverse - to allow us to see the crime and the alibi construction through the eyes of the criminal instead of the detective. Having unloaded the body from a British plane landing in France, Crofts flashes us back to the beginning of the drama. We are thereafter in the company of the young man who is facing bankruptcy, who hopes to tempt a rich young woman into marriage, and who has a rich uncle whose death could solve all the young man's difficulties.

So the fascination for the reader here is not in seeing how Inspector French moves from clue to clue in detecting and solving a crime, but in seeing how well the criminal can devise a murder and an alibi that will ensure he is never suspected or charged.

The result is eminently successful. To satisfy readers who expect Inspector French to feature in all his books, Crofts provides glimpses of him from time to time, lets us see him laying his hand on the criminal's shoulder towards the end of the book, and subsequently allows French to explain how he broke the alibi. Crofts provides further satisfaction by allowing French to be promoted to chief-inspector.