Although the title states "Professional", I think this book should find it's main audience in coding novices. Another problem with the title is the word ASP.NET in it. The book has one chapter covering ASP.NET, with only 35 poor-quality pages in it.
Now the title has some issues, but how was the content?
Danijel identifies codesmells and shows refactoring techniques to solve them. Too bad some of these examples are spreaded over multiple pages, which makes them a tad sloppy and hard to read. Danijel stresses how important Object Oriented design is. He proves this by transforming procedural code into Object Oriented code, greatly improving the readability. This book should help developers who are new to or come from a non-OO background to apply the basic Object Oriented concepts. Next to refactoring techniques, he also touches refactoring tools, unit testing and design patterns.
I think the beginning .NET developer might be able to significally start improving his codebase by reading this book. For more experienced .NET developers most of the topics handled in the book should be part of their day-to-day skillset.
All by all I was a bit dissapointed by the book, it was an easy read, had a few interesting tricks, but I expected it would go more into depth.
Something valuable I realised though.. is that refactoring isn't something you learn by reading a book, but you learn it by obeying the constant hunger for improving your code.
If you feel confident that you dig the basic concepts of writing quality code, I would instead of buying this book, invest in a good book on Object Oriented concepts or design patterns.