This chapter started with a discussion of the assembly, a logical unit of storage, deployment, and security within the .NET Framework. You saw how important it is and what a core part of the Framework it is. After that you got a taste of programming with assemblies.
From there, the chapter went into a discussion of AppDomains and AppDomain programming, illustrating some of the incredible power that you can add to your application simply by being aware of their existence.
Finally, all the new information was summed up by building a rudimentary plug-in system, including a host application responsible for locating and identifying plug-in modules. The goal of this chapter is to show you some things you might not ordinarily get a chance to use. Although you could easily spend your entire .NET experience without using an AppDomain or an assembly, perhaps you now see what you would be missing without them.