I bought this book in order to get a handle on creating add-ins for VS.NET and being an experienced add-in developer for VB6 I had high expectations, sadly not met. If you've never written add-ins before then this book will be useful to you because it provides useful information on how to add menus and toolbars to the IDE (always poorly documented in the MSDN), however, if you have you will be annoyed at the following:1) No explanation as to how to create your own dockable tool windows. (you need to create a user control and an ActiveX component to host it - MS provide a good sample on how to do this).
2) Very poor coverage of automation event handling, adding virtually nothing to the MSDN documents and sample.
3) Poor explanation as to why VB6 add-ins don't work in .NET (I'm not convinced that they don't yet) - I get the impression that the author has never developed add-ins in VB6 (only VB5) because his description of the extensibility interface methods refers to IDTExtensibilty, yet VB6 created add-ins implement IDTExtensibility2 (at least those created using the designer do).
Overall I get the impression that the author lost interest in the subject part way through the book or at least lost interest in solving the problems he obviously encountered. As I said, this book is good for beginners but not good enough for anyone with experience.
