This document introduces the MVC web framework CodeIgniter. It defines what a framework is and explains that frameworks provide a general application structure and handle common tasks, while libraries are used by code. The document then defines the MVC pattern, which separates business logic from presentation logic into the Model, View and Controller components. It provides examples of each component and how MVC is used for web applications. Finally, it proposes building a simple blog application using CodeIgniter to demonstrate MVC and the framework.