This is not a book on Ansible, and while I'm tempted to write one, there are already a considerable number out there (though truth be told, Ansible is so fast paced that you're better off learning as you go, and I don't usually advocate that). That said, I do like Ansible, and, along with the other tools listed in this chapter (Git, Terraform, Packer), it has made my life so much easier over the last couple of years that I've been using it.
There's something to be said for the idea that administrators are lazy, because all we really want to do is make our jobs easier, by automating away the tedious bits. We all used to joke that we'd end up automating ourselves out of a job one day, but some of the less lazy in our clan didn't like that idea, and seemingly decided that they were...