Some chapters are pure fun, and some chapters are difficult. Chapter 4 was a little of both for me. There is a lot of material in this chapter. To summarize, we spoke of three different programming languages and technologies: Reflection in Visual Basic .NET, regular expressions, and Intermediate Language. The uses of Reflection, regular expressions, and emitted IL code are likely new to many people.
The challenge for me was adding substantive material without writing 400 pages on this one subject. The challenge for you may have been that everything in this chapter was new to you, and learning about three languages is a tall order.
Regular expressions need a book of their own. Emitting code will need a whole book, too. When I wrote this chapter there were no whole books on Reflection in .NET and only an e-book on .NET regular expressions (a great one by Appleman ). Look down. That is the precipice of the bleeding edge.