I don't envy the author the task of introducing the simply vast subject of ADO.NET. What's frustrating about this book though is that the author doesn't really offer much by way of softening the blow of learning the topic. The introduction offers a the cheery counsel "[with respect to .NET and ADO.NET] ... We're all beginners now [...] Since we're all beginners, an exhaustive treatment would be, well, exhausting". And it's not until Chapter 9, around half-way through this 500 page book, that we're told "Given the disconnected nature of ADO.NET, there are four distinct phases to the processes of editing and updating data."
It would be tremendously helpful if this insight was given in the opening chapter and the subsequent material organised around these four stages. But alas, this only comes after the reader has been utterly bewildered by the density and complexity of the information given about the ADO.NET object model. For my tastes, more précis is required and more illustrations of WHY the functionality of ADO.NET is useful, rather than dry encyclopaedic bumph.
If you want a detailed - but apparently not exhaustive - introduction to a very complex subject, this book will deliver it. You'll probably, like me, end up writing out about 10 side of A4 of notes to help distil it down. If, also like me, you would like a "zoom out" view before being paint-balled with the detail, read Thearon Willis' "Beginning VB.NET Databases" before tackling it.