The last one was (https://www.econlib.org/open-borders-is-a-new-york-times-bestseller/), which sounds terribly impressive, until you realize that "Graphic Novel" is a pretty niche corner of the list. But it is something!
His next book is described on his homepage (http://www.bcaplan.com/). As far as I'm aware it is still due out in early 2023.
I will update the close of bidding once the release date of the book is known. It will probably close a few days after the book comes out, but before it is possible to have direct knowledge of the items on the NYT list.
Sep 2, 3:36pm: He recently stated that it's now slated to appear in the fall of 2023, unfortunately.
Close date updated to 2023-09-01 11:59 pm
Note that in Caplan's own terms, he calls Open Borders a "nonfiction graphic novel", i.e. he treats "graphic novel" as a medium that is often used for fiction but also can be nonfiction, as in the case of said book. His forthcoming Build, Baby, Build is also intended as a nonfiction graphic novel.
As Open Borders was already published at the time of this market's creation, the resolution should be based on Build, Baby, Build, which currently has a (much delayed) expected publication date of April 2024. Of course, if somehow he should publish a different graphic novel (nonfiction or otherwise) before it, that other one would be the relevant book for this market. But under no circumstances would an already-published book be the relevant one.
@zzq Agreed.
Seems like this would be more interesting to re-open until an appropriate time? That seems to fit with the previously demonstrated creator intent.