You may be interested to know that the story for The Maltese Falcon, not listed, will also be entering public domain because it was published in monthly installments in Black Mask magazine before it was published as a novel. (Any changes between the publication in Black Mask and those made for the novelization, if significant enough, will of course still be under copyright and so the novelization proper still won't be entering public domain for another 13 months.)
We have had difficulty getting our hands on these issues, though (or scans of them).
It's interesting that AMC just launched a series featuring Sam Spade this year, the year before the character goes into the public domain…
Those of us trying to get them scanned in and online.
Black Mask is pretty rare. Brooks Hefner at James Madison University oversaw the acquisition/accession (I think) of their Black Mask collection, of which they have quite a bit in comparison to other places, but it's still incomplete. The Ransom Center in Austin specializes in rare and collectible items, but only has one or two issues. The Library of Congress may well have a complete collection, but what they do have isn't digitized because the pages are brittle and are literally falling apart (even moreso than other/older printed material).
We have had difficulty getting our hands on these issues, though (or scans of them).
It's interesting that AMC just launched a series featuring Sam Spade this year, the year before the character goes into the public domain…