"When it came time to revise our coverage of C# and CLR support for interop
with COM objects and services, we decided that interest in these topics had
declined to such a low level that we could drop them from the book. As a
result, two  C# in a Nutshell Second Edition chapters ended up on the
cutting room floor: Chapter 18, "Integrating with COM Components", a
tutorial on the subject; and Chapter 37, "System.Runtime.InteropServices," a
reference on the types that support C# interop with unmanaged code. 
 
"Nevertheless, we understand that COM interop will remain an important
subject for programmers working with legacy Windows code, so we've posted
those chapters here. You're free to download them and use them, in your
work. If you disagree with our decision, please write and tell us what you
think we should do for the next edition of C# in a Nutshell."