One easily-overlooked fact about the table view is that no matter how simple it might seem to use one in your app, it's one of the more complex components of UIKit. Some of the complexity is exposed when you add a table view to a regular view controller instead of using UITableViewController. For instance, you had to manually set up the layout, so your table view covered the viewport. Then, you had to manually set up a prototype cell to display data in.

The next step toward displaying contacts to your user is providing the table view with information about the contents it should show. To do this, you must implement the data source and delegate for the table view. These properties use advanced concepts that you may have seen before, you probably just weren't aware of them yet. Let's make sure you know exactly what is going on.