The book covers the basic idea of D3. Nothing more. I know jQuery, which helps a lot, and this book really helped me to understand the idea behind D3.
I would not recommend this book for anything except a "Getting started" / "Read before your try-and-error journey". D3 "getting started" tutorials are rather sparse on the web, and this book fills the gap. It rush through the 3-4 most important charts (line chart, bar chart, stacked bar chart, time series) and finishes with a nice bonus: how to create a directed graph.
Less than 8€ for a kickstarter is worth it. But don't expect anything like a reference or a long-living valid book. D3 is still a young project, and techniques around d3 are still emerging. It would be nice if the book would go a bit more into the details of D3 or if it could cover more examples. I did not regret buying the book and would recommend it to anyone considering d3 (without knowing how to get started).