1) Even the earliest Continental Op stories have that twist ending that casts into question all that has gone before, or comes as a comic anti-climax, or seems almost to be the beginning of a new story before the old one has ended.
2) The first great Op story was probably "Zigzags of Treachery" — and here I welcome comment from readers more up on their Hammett than I. I don't know how critical consensus ranks the Op stories. "The Golden Horseshoe" is the best of this batch I've read in recent days.
3) Hammett's experience as a private detective is often cited as contributing to the authenticity of his writing. It does this in the Op's convincing asides about detective work (good shadowing, the Op tells us, perhaps ironically, is not as hard as one would think), but also in observations like this:
"Little things, those, but a private detective on the witness stand—unless he is absolutely sure of every detail—has an unpleasant and ineffectual time of it."4) Hammett's novel Red Harvest was made into an opera, which elicited the observation from the Thrilling Detective Web Site's Kevin Burton Smith that "I guess it won't be over until the Fat Man sings."
Go here for a compact but thorough discussion of Hammett's short fiction, including a typology of his plots.
© Peter Rozovsky 2010