With all of my rave reviews of this series, I probably sound like I work in their PR department, but seriously, I don't. Every single book in this series that I've read is just plain great. This book, as well as their ASP.NET 2.0 title are just more examples of the same killer material they are publishing.
The book splits itself about 60/40 ADO.NET 2.0 Per se and the XML. However, if you're familiar with ADO.NET, you'll know they are interdependent technologies in .NET (no, I'm not saying you can't use XML without ADO.NET but XML and ADO.NET are so intertwined in .NET,it's hard to talk about ADO without XML).
Anyway, there's little in the way of review for the way ADO.NET used to work, and Amen to that. This book is short and too the point and you don't need to undestand pervious versions of ADO.NET to understand what's going on. With that in mind, a long discussion of previous version would be a waste of space. Now, there's no doubt that this book emphasizes Yukon and SqlServer features of ADO.NET 2.0, but it's not in any way limited to that. The subject of Batch updates is very cool (I know I can't wait for 2.0 to be released) but it doesn't take a lot of explaining. MARS and ObjectSpaces get a lot more coverage, but those are the two coolest features that I've seen. Well, that's not entirely true, the bulk loading features and paging are pretty darnded cool too.
Then the book discusses Yukon and the only complaint I have here is that I can't get a copy of it! You'll need Whidbey to compile the examples, but I've found getting a copy of Yukon to be quite elusive so that is somewhat limiting. However, that's not the author's fault in any way. (However, if they want to include a copy of it with the next release of the book, it'd certainly be a nice touch).
After that it moves into the XML realm and it's very very cool. No, it doesn't walk you through creating an XML document. The focus is heavy on data extraction with XML, XPath, XQuery, XmlReader, XmlAdapter taking up the focus of the discussion. Trust me, you'll be dying to play with this stuff by the time you get through the first discussion on it.
All in all, it looks like ADO.NET 2.0 is a larger evolution from previous versions than ADO.NET was to ADO (although ADO.NET is a totally different technology than ADO). If you want to take advantage of these features, you're going to have some learning to do. However, all of the books examples are complete, concise and clear and most importantly, they all work. There's nothing worse than typos and broken code, but it's a lot worse when you are dealing with a technology this young.
Once again, another first rate job by A-W.