This part of the book introduces packages, the most important construct in PL/SQL for building reusable code and employing object-oriented design techniques. Chapter 1, PL/SQL Packages describes how and when you should create packages and explains why PL/SQL developers should learn to center their entire development process around packages. Chapter 2, Best Practices for Packages presents my tried-and-true "best practices" for building packages. Chapter 3, The PL/SQL Development Spiral puts packages in the context of overall PL/SQL development by providing a tutorial on solving a typical problem in PL/SQL .