Nice post! Short and simple to read. Is epublish on GitHub or somewhere? It looks simpler than previous approaches I've seen.

I had the chance to help a bit with one of the AOSA books. It was a very powerful pipeline, but also quite complex to manage. IIRC it used pandoc (and a lot other tools).

So having a simpler alternative like epublish would be interesting if I have to work on another book in the future.

EDIT: sorry, just went to the main thread, and saw there you replied to another user it's not open source "yet" (hooray)