It couldn't have been suicide - the victim was beheaded inside a watched and locked room - but the room was empty, except for the victim. French police director Henri Bencolin stars in the first novel by John Dickson Carr.

A theatrical and criminal problem for Ludovic Travers to solve.

Right from the start, it was clearly going to be an interesting case – the murder of an inoffensive little man with no apparent enemies, not much in the way of physical clues. And that kind of case can be very frustrating indeed.

What connection could there be between a gruesome fire in a London house and a ski holiday in Lech Am Arlberg in the Austrian Alps? The answer may conceal a ruthless murderer.

Princess Olga Karukhin escaped from Russia after the revolution. Was she murdered for her supposed collection of art objects?