Found 2 comments on HN
I was looking for the book, but your link didn't work for me, this one did:

lostcolony · 2014-01-14 · Original thread
I don't know how good the tutorials for Elixir are on teaching you the basics of concurrent programming on the Erlang VM. It's very different than the concurrency models you'd encounter in almost every other language (Scala, and the Akka framework not withstanding, since they basically borrowed everything from Erlang and implemented it on the JVM), so it's not merely a matter of learning syntax and a couple of new constructs; your entire mechanism of problem solving changes (I'd almost argue that Erlang is unique in being a 'concurrent language' rather than, say, an OO one, or procedural, or functional. It's functional, yes, but its concurrency mechanism is messages, which have no guarantee of delivery, so are by definition side effects).

As such, I'd recommend starting with Erlang rather than Elixir simply because you'll find tutorials on how to start thinking about and breaking down problems to take advantage of the environment; trying to write an Erlang app using a paradigm learned from another language is going to be frustrating and not performant.

Joe released a 2nd edition of Programming Erlang last year, which is a -really- good introduction to the basic ideas of the language, as the focus of it (as compared with the first edition) is very much beginners, and taking advantage of the platform.

Get dozens of book recommendations delivered straight to your inbox every Thursday.