As for tool stack recommendations, I would think the answer is highly subjective, the choice of which depends on many factors including existing technology used and capabilities of both your development and operations teams.
I just had a chance to browse through the book. One interesting thing to note: Chapter 5 of the book is about Misconceptions and Antipatterns of DevOps. One misconception mentioned is that DevOps is all about the tools.
Our guest authors wrote:
While tools are valuable, devops does not mandate or require any particular ones... Devops is a cultural movement. Within your environment the tools you use currently are part of your culture. Before deciding on a change, it behooves you to recognize the tools in the environment that have been part of the existing culture, understand individuals’ experiences with those tools, and observe what is similar and different between others’ experiences. This examination and assessment helps clarify what changes need to be made.
Angus, in what way do you want to understand DevOps? Are you looking to learn how it can improve your current environment? Are you looking to level up your skills? The very first paragraph of Chapter 1 "The Big Picture" in Effective DevOps has this definition for you:
Devops is a way of thinking and a way of working. It is a framework for sharing stories and developing empathy, enabling people and teams to practice their crafts in effective and lasting ways. It is part of the cultural weave that shapes how we work and why. Many people think about devops as specific tools like Chef or Docker, but tools alone are not devops. What makes tools “devops” is the manner of their use, not fundamental characteristics of the tools themselves.
Based on your answers to the previous questions, I can point you in the direction of how to gain insight. As Junilu mentions, the answer is highly subjective based on your current environment, and your current needs.
Browsing further into the book, I found that Chapter 13 discusses tools and common misconceptions about them. One misconception about tools: using Technology X means we're doing DevOps. That's a great callout. Just as using the same golf equipment that Tiger Woods uses doesn't necessarily make you good at golf, your use of the same tools that are commonly used for DevOps doesn't mean you're doing DevOps. I think that valuing "Individuals and Interactions over Processes and Tools" is equally important with DevOps as it is with Agile development.