I'm doing an MSc in Data Science and one of the requirements was to learn Erlang. I read this and the Erlang Programming by Cesarini/Thompson. Sadly I did the other book first and got totally lost. This introduction however was a life saver and made concepts clear and give me enough to code. It was particularly helpful with the parallel processing element which seemed clearer in the intro than the programming book. At 184 pages it is short but just right to pick up Erlang. Managed to code to produce code beyond the basics within a week.