title: What describes the Application Delegate best? How does it fit into the whole concept?
body: <p>I think to know what the App Delegate does. It has some nice methods like <code>-applicationDidFinishLaunching</code> which will be called when the app has finished launching, and so on. But what's that actually? Is that some object instantiated in the <code>UIApplicationMain</code> function?</p>
  
  <p>And how does it work that every class in my app has access to that App Delegate object? Is there any good graph on the net that visualizes these relationships?</p>