While in portrait mode, the master view controller is missing in action. It would be nice if you could see the master view controller to select a new post from the list without having to rotate the device. UISplitViewController lets you do just that by supplying its delegate with a UIBarButtonItem. Tapping this button shows the master view controller in a UIPopoverController (Figure 26.5).

In your code, whenever a detail view controller was given to the split view controller, that detail view controller was set as the split view controller’s delegate. As the delegate, the detail view controller will get a pointer to the