In this chapter, we looked at the MVC architecture and outlined the needs of having an MVC architecture implemented on the client side, which runs inside a browser. We then went on to see how we could have modeled our application without using Sencha MVC architecture and looked at the demerits of that modeling. We then looked at the benefits that one can get by following Sencha MVC architecture. Subsequently, we looked at the classes in Ext JS as well as Sencha Touch, which map to the model, view, and controller. In the following chapters, we will delve deeper into the specifics of the Sencha MVC architecture where we will see how to create an application using the Sencha MVC Architecture.