Just wanted to add in another update (in case OP is still following this thread); I’m halfway through a new book on Ansible, Ansible for DevOps. My aim is to take developers and sysadmins who may or may not be using any automation for their infrastructure, introduce Ansible and infrastructure automation, and keep things short enough to be readable but long enough to be meaningful.
Instead of publishing with a traditional publisher, I’m using LeanPub, which allows me to publish updates as I write them. When I started on the book, Ansible’s latest release was 1.3.x, and it’s now almost 1.7.x. Whenever there are large changes, or when one YAML syntax style starts becoming a de facto standard, I update the book and incorporate those changes.
In the long run, my goal is to always have the published edition of the book match the latest version of Ansible, and it’s actually not too hard to do that using LeanPub 
I’d also like to echo Michael’s point about referring first to the docs; Ansible’s documentation has improved radically since I started using Ansible, and you can really go from 0 to 60 on the main docs. I’m hoping Ansible for DevOps can then take you from 60 to 100 in a decent amount of time
-Jeff Geerling