The Data Source Handbook is a *very* short book with ideas for using APIs to extract data from various web sites. This is definitely a book for developers only, as a knowledge of JSON, XML, scripting languages and utilities like curl are assumed.
While reading through the book generated some thoughts on where this data could potentially be useful, in the end I found this book disappointing. Many of the sites/APIs discussed are limited in terms of function, volume or stability; most of them could be discovered with a Google query. For example, the (US) National Weather Service section provides a working example using curl, but the NWS site itself provides multiple client examples in various languages. The NWS site would also be updated as their interfaces change, not necessarily true of the book.
The ebook version provides links to the author’s blog for additional information. Unfortunately the blog itself doesn’t seem to have a segregated page or segment dedicated to the book.
At a low price point, a book of this size (ebook version is 30 pages) could be useful if you’re just looking for something to explore new concepts. Otherwise, probably not a good value.