1.2 …get the most from this book
Firstly, forget DevOps. Seriously, ignore it. Although this book uses the term DevOps (mostly for marketing reasons) it is really more general, it is about how to do IT System Lifecycle Management more effectively. DevOps is a distraction at worst and only a small part of sucessful IT System Lifecycle Management at best.
I’m assuming you’re primarily interested in the technical parts of this book. If so, do the examples! You’ll get much more from the material by following along and investigating for yourself. As for the non-technical parts of the book, read them as general advice and observations, not hard and fast rules. More people fail with IT System Lifecycle Management simply because they try to implement DevOps, ITIL, etc. as hard and fast rules rather than guidance.