The iPhone and iPod touch have a limited amount of screen real estate. Given their small screen size, when presenting a drill-down interface, a UINavigationController is used to swap between a list of items and a detailed view for an item.
The iPad, on the other hand, has plenty of screen space to present both views using a built-in class called UISplitViewController. UISplitViewController is an iPad-only class that presents two view controllers in a master-detail relationship. The master view controller occupies a small strip on the lefthand side of the screen, and the detail view controller occupies the rest of the screen.
In this chapter, you will have Nerdfeed present its view controllers in a split ...