As I just said, we will be building a web application. But we will try to lay out some details beyond that. So the web application that we are building will be based on ASP.NET MVC. We will have conceptual layers in this application such as business/domain layer, data access layer, presentation, and so on. But these layers will all be in the same process at runtime. We will not have each layer running in its own process like a standard 2-tier or 3-tier application. However, everything that we discuss here can be extended and applied without many changes to 2-tier or 3-tier applications separated by process boundaries.