I finally got around to reading Whose Body?, first of the Dorothy L. Sayers' Lord Peter Wimsey books. At the time, I did not realize it was the debut, partially because the copyright for some reason did not have the original date of publication. Nor would I have guessed that this was the character's introduction had I not later read it on Wikipedia.
It does not feel like an initial effort. The personalities, the relationships, and the back stories are all completely thought out. It seems like a perfectly representative book in the series.
What did strike me as unusual was the contrast between this story and the conventional Edwardian detective novel. (I realize, of course, that the novels I am thinking up were not actually Edwardian. However, like the adventures of Bertie and Jeeves, they usually had a distinctly Edwardian feel.)
Lord Peter, by comparison, has a distinctly postmodern field. Whose Body? is to the standard Golden-Age detective novel what Scream is to the Friday the 13th series. It mostly follows the rules of the genre, but self-consciously and only as long as they could be reconciled with the way the world actually works.
Wimsey plays the role of Edwardian twit with amused self-awareness, as does Bunter, his perfect gentlemen's gentleman. It is strongly suggested that this role-playing is, in part, therapeutic. Wimsey left the war severely shell shocked and was still suffering relapses in 1923. Bunter, who had been Wimsey's batman during the war, had taken the job as valet in order to help his commanding officer recover. The scene where he takes Wimsey back to bed after a relapse is remarkable for its tenderness.
Bunter is also notable for his talent for forensics, which brings up another distinction of the series. Unlike most mystery writers of the time, Sayers was genuinely interested in the science of detection. (even more notable in The Documents in the Case).
The real world intrusions continued even after the cases ended. Sayers made Wimsey painfully aware of the consequences of his actions. In 1923, catching a killer meant sending him to the gallows which meant that most of the novels ended with a private trauma for the hero.