We began our chapter by looking at application architecture. We discussed various methods that can be applied to create an architecture. Additionally, we identified several key characteristics of modern applications. Then we identified the modern software management principles that allow consistent delivery of successful applications, and moved on to discuss the Enterprise Application Model and its six submodels: the Business Model, the User Model, the Logical Model, the Technology Model, the Physical Model, and the Development Model. Each of these submodels was examined in turn. Finally, we looked briefly at the MSF Application Model for Development. This MSF model discussed three-tier application architecture with User Services, Business Services, and Data Services.