In a layered Web app, the presentation layer is just as important as navigation logic, business logic, and data access. While you should try to keep the presentation layer (mostly the presentation logic) independent from the UI technology and platform, it's not always easy to do. Design patterns can help. In this month's column, I'll examine some design patterns for building an ASP.NET presentation layer. I'll start with the Model-View-Controller (MVC) pattern—the root of all patterns specifically targeted to the UI—and discuss its applicability to ASP.NET beyond the ASP.NET MVC Framework.