Hi all, I really need some help and suggestions about organize the view hierarchy in my education app. In my app, it consists some view controllers as below: 1. Menu View Controller - consists level buttons example: 'Level 1', 'Level 2'. 2. Level View Controller - show the questions for each level. For example: When user click 'Level 1' button in Menu View Controller, this level view controller will show a view and display a number of questions let user answer. 3. Result View Controller - show the result once user finish answer the questions. In this result view controller, it consists (a) 'Play Again' button - Once click it, will switch back to Level View Controller so user can play again. (b) 'Back to Menu' button - Once press it, it will switch back to menu view controller. (c) 'Play Next Level' button - When click it, it will switch to Level View Controller which will show different set of questions. I am not sure how to organize these view controller in a better way since it always need switch between the existing view controllers. Before this I am adding a view controller as a subview of another view controller to achieve 'switch view' purpose but it seems not a good practice. Am I need use navigation controller? Currently I am reading the view controller programming guide. But really hope someone can share their idea, suggestion and experience. Any comments are welcome. Thanks a lot.