Added navigation bar but there is no back button?

Embed the TableViewController inside the NavigationController. Not the DetailViewController directly. Check out the screenshot.

Make sure, that the segue, connecting your TableViewController and your DetailViewController is of type Show (e.g. Push). You have to literally push a new View on top of the Navigationstack.

Click on the StoryBoardSegue, the link between the tableviewcontroller and the detailviewcontroller. In the attributes inspector you may need to click on the "Animates" check even if it is checked. Do this after selecting "Show(e.g.Push)" located in the "Kind" drop down menu. Then run your app and then reselect the same "Animates" option after stopping your app. I think this is a bug and it took my an hour to figure out how to solve this. Additionally, you can use the deprecated "Push" but this will illicit a warning. Deprecated "Push" is under "Kind" in the StoryBoardSegue attributes inspector.

I've had the same issue just now, resolved by deleting segue, adding again and giving it an identifier straight away.