[fvt]

OP here. Just came across it and I found it was interesting enough as there's not so much books about Docker.

[Alupis]

There aren't a lot of books about Docker because by the time they get published, Docker has made so many breaking changes, they are irrelevant.

[fvt]

While you're definitely right when it comes to printed books, self-published books tend to be pretty up-to-date (as an example, I believe "Agile Web Development With Rails" runs a test suite against Rails and the author gets notified the moment something's not accurate with the book, maybe it's the case for this one).