That's the first Erlang book, and is very good. Unfortunately, it's out of print, or was the last time I checked, but might be available used. It's very good for wrapping your head around programming with pattern matching, single assignment, and message passing concurrency, but light on the OTP, since, I believe, it was written before much of today's OTP was written. Think of it as the book the writers of OTP must have used to learn how to write OTP.

If you can find a used copy, grab it. I bought mine when it was still in print, and wouldn't part with it.