L. Frank Baum (1856–1919)

This is one of five books I purchased at a bookstore, and I suspect someone bought the entire series in 1919--after the publisher changed its name from Reilly & Barrow to Reilly & Lee. With that in mind, I think of these five, the only one that's the original edition is the 1919 book The Magic of Oz, which was published a month after L. Frank Baum died.
So... this is an early but not quite original edition.

This is the last Oz book L. Frank Baum wrote before he died and Ruth Plumley Thompson wrote another 19 books.
Not absolutely sure, but I think my copy is the original edition.
It's possible someone purchased the entire series in 1919--I purchased 5 antique Oz books at a bookstore, and it turns out some of the first editions have a slightly different name for the publisher (Reilly & Barrow instead of Reilly & Lee), and cover art with a more limited color scheme.

This copy is antique and has the same cover as the original edition. It might be a few years later, though, since the publisher changed its name from Reilly & Barrow to The Reilly & Lee Co.

It's been a while since I read this series--I'd like to read it again soon.