XAML, a dialect of XML, has been especially important since its introduction with the first version of WPF in 2006. It is often misunderstood to be just a way to specify user interfaces, much like HTML. By the end of this chapter, you will see that XAML is about much more than arranging
controls on a computer screen. … In Windows Workflow Foundation (WF) and Windows Communication Foundation (WCF), XAML is used to express activities and configurations that have
nothing to do with user interfaces.The point of XAML is to make it easy for programmers to
work together with experts in other fields. XAML becomes the common language spoken by all parties, most likely via development tools and field-specific design tools. But because XAML (and XML in general) is generally human readable, people can participate in this ecosystem armed with nothing more than a tool such as Notepad.