Howdunit makes good on its promise of offering "A Masterclass in Crime Writing," so long as you define "masterclass" as "a class taught by masters." All the notes and essays in this book are written by highly accomplished writers of crime fiction. The title is a riff on the slang for murder mysteries as "whodunits." The emphasis here is on how to write one.
Naturally some are just what I'm looking for while others are remotely interesting. I'm working my way through the book, marking essays that speak to the challenges I'm facing at the moment in my writing and finding quite a few that do.
For instance, I am benefiting from Andrew Taylor's essay, "How to Change Your Murderer." The title refers to some writers who say the started off thinking they knew who murdered whom, and ended up changing their mind by the end of the first draft. Taylor uses this as an example of how unplanned a plot can be.
The Detection Club was founded in 1930 with G. K. Chesterton as its first president, and has counted such all-time greats as Agatha Christie and Dorothy L. Sayers in its membership as well as many contemporary writers. Since it's a British club, all the essayists are British, though they have good things to say about the likes of Edgar Allen Poe, Raymond Chandler, and Patricia Highsmith.