A feature that greatly contributed to making Visual Basic one of the most popular languages for Microsoft Windows programming is its ability to create ActiveX components and controls. As you'll see in this chapter, creating an ActiveX component is an easy process, and in most cases you can turn a class-based application into a component simply by changing a few project settings. This shouldn't be a surprise; after all, classes were introduced in Visual Basic 4 with their main (or only) purpose being to help in the delivery of COM components. This move was necessary because Microsoft intended to propose Visual Basic as a language for developing complex multitier client/server applications.