The Franchise Affair (reviewed here), but The Singing Sands knocked my fandom up to the next level.
Alan Grant works for Scotland Yard and is on the brink of a nervous breakdown. He catches a train, looking forward to a much needed vacation, only to discover a dead body in compartment B-7.
Who is the dead man? How and why did he die? Typical questions for a mystery novel. But the book diverges from the commonplace with it's atypical detective. The protagonist makes this novel twice as interesting as he struggles with his various demons. Conversations he has with his alter ego are laugh-out-loud funny. Even after the name of the dead man becomes known, in Grant's mind he is often referred to as "B-7." I loved how the mystery helped lead him to healing and wholeness.
All of the characters are wonderfully drawn. The writing is top-notch:
Grant had the island to himself, and for five days in the company of the whooping wind, he quartered his bleak kingdom. It was rather like walking a bad-mannered dog; a dog that rushes past you on narrow paths, leaps on you in ecstasy so that you are nearly knocked over, and drags you from the direction in which you want to go. (p. 86)
Charmingly British, The Singing Sands was Tey's last novel. Alas, no more Alan Grant! In spite of some off-color language, this is a splendid read.