Garon’s answer to “Are there any plans for Penumbra to be released in physical form?” > Likes and Comments

Okay, the issue isn't with listing it; the issue is with linking it! Apparently, it's listed, but all by itself. It's not on the same page as the Kindle or Audio versions. I'm working on getting that fixed.
Meanwhile, go to Amazon and search for "1836020287"
Penumbra's hardback version should show up in the results!
(Note that it SAYS it's "leather-bound." It isn't. It's should be the same as all the other hardbacks in the series.)

There it is. All of the searches bring up the Kindle or audiobook versions. You're awesome!