Part 6, consisting of Chapters 13-17, covers important parts of the .NET Framework that are useful in creating a variety of different applications. Chapter 13 covers ADO.NET, which provides a consistent set of classes for accessing both relational and XML data. Chapter 14 introduces the fundamentals of ASP.NET, including the use of Web Forms, for the development of Web sites. Chapter 15 covers SOAP and Web services, which provide an easy-to-use and robust mechanism for heterogeneous systems to interoperate. Chapter 16 covers the topic of security in detail, including Code Access Security and declarative security. Chapter 17 covers interoperability of .NET with legacy COM and Win32 applications.