Hi Raymond,
Thanks for welcoming us
We try to cover all grounds in the book: the first two chapters should help you get started, then chapters 3-8 focus on managing the mapping and the queries (how to index data, how to set up text analysis, how to make queries relevant, how to manage relationships, how to run aggregations to get real-time statistics). Chapters 9-11 focus more on administration (scaling, performance tuning, monitoring). Appendices cover features that are very nice, but maybe not needed by everyone (like highlighting or monitoring tools).
At the moment, the book is written on 1.4.x. The final version will include all upcoming changes in the 1.x branch (what you'll see in 1.5 and probably 1.6) and account for what we know will change in 2.0. We're trying to future-proof it as much as possible - most things remain the same, but there are important differences that we need to point out, especially when it comes to best practices.
You can use Sense, but it's now part of Marvel (a commercial monitoring product by Elasticsearch which is free for development). Alternatively, you can send requests from your browser with plugins like Head and Kopf. I personally use curl most of the time, and you'll see curl examples in our book as well.