Who knew that A. A. Milne wrote novels for adults, let alone mysteries? I didn’t, until Simon of Stuck in a Book reviewed The Red House Mystery. Then I saw it advertised in Folio Society, of which I am a member.
Our detective is an amateur, Antony Gillingham, who comes on the scene accidentally. He is visiting in the area when he remembers his friend, Bill Beverley, is staying at the Red House, a guest of Mark Ablett, so he decides to drop by. He finds a man hammering on the library door. This man is Mr. Cayley, Mr. Ablett’s secretary, who reports he has heard a gunshot from within the locked office.
Cayley and Antony break in and find the body of a man who has been shot in the face. Cayley identifies him as Robert Ablett, the ne’er-do-well brother of Mark, just arrived from Australia. Mark Ablett, who had been in the room with his brother, is nowhere to be found. The police decide Robert has been murdered and begin looking for Mark.
Antony begins noticing clues about the crime. Enlisting his friend Bill as his Watson, he decides to solve the mystery.
With typical Golden Age verve, Milne makes this puzzle just about as complicated as possible. I usually don’t hope to solve these mysteries because of that. However, I did guess at part of the solution and then decided it wasn’t possible. Apparently, it was.
What I enjoyed about the book was the congenial duo solving the crime. Antony is bright and witty, and Bill is jovial and loyal. The Red House Mystery makes a fun light read.
whatmeread 
I read this last year and I enjoyed it too. I wish A. A. Milne had written more books like this.
It was fun! I’m sure I read your review, too.