The author begins with a tour of ActiveX and COM, along with some common myths about the technology. His introduction to COM technology is good, but Appleman also explains the pros and cons of COM objects used as in-process dynamic-link libraries (DLLs), standalone EXEs, and remote processes.
When it comes to Visual Basic, the author gives plenty of expert knowledge on class and project options. He covers how to design objects in Visual Basic up close and includes some hard-to-find material on collections and multithreading programming techniques. Appleman also provides an interesting example, a live stock-quote server.
A good deal of the book concentrates on writing ActiveX controls in Visual Basic. Although some developers use the Active Template Library (ATL) and Visual C++ for high performance, it's clear that Visual Basic can do a fine job of creating reusable controls. The author presents a soup-to-nuts tour of ActiveX control development, with due consideration of such topics as properties, events, property pages, and even security and signing. Final sections on ActiveX Documents and the new Visual Basic 6 WebClasses (for ASP development) show off Internet development. In all, this book offers much useful material on expert-mode topics geared to the more seasoned Visual Basic developer.