Crimeline (electronic reprint of 1937 original)
Rex Stout made several stabs at establishing lead characters in mystery novels, besides Nero Wolfe. He wrote three books featuring Tecumseh Fox [Double for Death (1939); Bad for Business (1940); The Broken Vase (1941), Alphabet Hicks [The Sound of Murder (1941), and Inspector Cramer (although he’s not really the central character) [Red Threads (1939)]. But the first of these was The Hand in the Glove: A Dol Bonner Mystery (1937). In this instance, even the title suggests that he saw this as possible the first in a series, and Dol Bonner as possible a continuing character.
And in a sense, she was. She has a part in Bad For Business (although she is depicted less positively), in the novella “Too Many Detectives” [collected in Three for the Chair (1957] and in If Death Ever Slept . But she never again had a leading role. In The Hand in the Glove, Bonner has opened a detective agency (with seed money provided by her friend Sheila Raffray, the orphaned daughter of a wealthy man), and the case develops from her relationship with Raffraty—she is hired by Raffray’s guardian, P. L. Storrs to remove George Leo Ranth (who is the proprietor, I guess we could say, of the League for Occidental Sakti) from his wife’s circle of acquaintances.
This involves Bonner’s travelling to Storr’s house (Birchhaven) in the NYC suburbs. She arrives to find a cast of characters including Martin Foltz (Raffray’s fiancé), Wolfram de Roode (Foltz’s long-time employee) Len Chisholm (fired as a reporter by The Gazette for writing a story that disturbed Storrs), Steve Zimmerman (a psychology professor with more than a few quirks), Janet Storrs (P.L.’s daughter), Ranth, and Mrs. Storrs. In short order P.L. Storrs winds up dead, strangled in the rose garden.
The law arrives and begins an investigation—D.A. Daniel Sherwood, Colonel Brissenden of the state police (who turns up, as I recall, in one of the Wolfe stories), assorted other police—and Inspector Cramer (although why remains a mystery to me). Bonner has formed an intention to carry out her own investigation, and announces that intention to the police.
The investigation seems to me to be well-handled on all sides, although not much progress is made. I think I reveal no secrets by saying that Bonner figures it out, and quite nicely. All in all the story is nicely set up and fairly plotted and a very good read.
This is right up near the top of the non-Nero Wolfe books that Stout wrote. For myself, I would happily have read more about Fox the ‘Tec, about Hicks, and, especially, about Dol Bonner.
 As I recall, Stout also reuses “Birchhaven” as the name of a client’s estate in In the Best Families, a Nero Wolfe novel published in 1950.