I would say that Terraform is the most unsophisticated tool from Hashicorp that I know. However, if you're thinking that's a bad thing then you're wrong.
It does a bunch of things that anyone else who has a glimpse of AWS/Openshift/Azure/etc SDK plus a bit of any scripting language can easily do without loosing a sweat.
But that's its main ace in its sleeve. It does a simple thing and does it very well. It encapsulates all the knowledge about different providers in itself allowing you to use one interface amongst them all.
Considering what Terraform is I would say that this book is too much long and it goes in too much detail. But as with Terraform itself that's not bad because the more you know the less you fear. And this book allows you not fear Terraform and be productive with it since the very beginning.
My score is 5/5