The Problem of the Wire Cage by John Dickson Carr published in 1939 features Detective Gideon Fell. Brenda White's marriage is arranged to Frank Dorrance by their guardians. The only way they both would inherit the enormous money their guardian has left would be my marrying each other. Or. Oh! Yes! There is always an Or. Or the other one drops dead. So it is not a surprise that Frank Dorrance drops dead. The vital question is not who or why but how. If you figured out the how, you can later figure out who or why. How did anybody kill Frank?
This is a locked room mystery with a twist. Only the murder is not in a locked room but inside a tennis court, one caged on all sides except the entrance. It has rained heavily, meaning anyone entering or leaving the tennis court will leave footprints. There are just two pairs of prints one of the victim, the other of his fiancée, who swears she didn't kill. After all she is the heroine, it doesn't look like she killed. Maybe she did. But if she didn't, who killed and how? We will come to the why later. How can you strangle somebody in the centre of the tennis court without leaving footprints? There is another complication. One of the suspects is an acrobat. Did he do a tightrope walk to kill his victim? Is it possible? And how far one would go to kill somebody without leaving evidence.
There is of course a simple logical solution. I didn't figure it out. I couldn't help wondering the lengths people go to protect themselves. Is it really possible? Until the final explanation, I had no clue on how it was done. And I do really wonder if it is possible. Very entertaining. A classic Howdunit!