The discussion thread is up.
One thing I hadn't noticed before is that, even if we'd gone with a 20s decade topic as we were close to doing (books written or set in the 2020s, 1920s, 1820s, etc.), this book would still have fit!
Also, it's almost exactly 100 years old. It was published in 1921, so there's a chance he was working on it exactly 100 years ago anyway.