If you already have done Elixir from other sources and you fill you are grasping the syntax, then you can go ahead and buy the book. To me was the only book that clicked to make the transition from Object Orientated code to Functional Programming.
You may also want to see the Elixir for Programmers video course from the same author:
You may enjoy more doing the video course, but only do it if you are already comfortable with the basics of Elixir. No need to know about OTP and all the advanced stuff, because the book will teach you that.
Got for it after you have done one of the above 
