I purchased two copies a few weeks ago from Unbound here: https://unbound.com/books/cains-jawbone-paperback/

It shipped from overseas and, as usual, was stuck in US Customs for about a week, but this was in the run-up to the holidays. Might be faster now.

Woah! It was listed as “sold out” on the Unbound website only hours ago. Thanks!

amazon.com claims to have it, although only as a paperback, not as the nicer collection of loose pages.

Amazon should print the book in the correct order.

When Black Mirror's Bandersnatch came out, I had it added on Plex. I watched it before I knew the concept behind it. All of the multiple storylines were played sequentially. I remember thinking, wow, way too avant-garde for me. It was only later that I realized that Netflix had an interface built around it for picking the storylines.