No, back is undo on a certain level of granularity. You need to figure out which actions in your application intuitively correspond to the "back" operation, and

No, back is undo on a certain level of granularity. You need to figure out which actions in your application intuitively correspond to the "back" operation, and make the back button actually do that. Undo could be for a finer grained edits, like edits within a certain "page" of your app. Seet the new GMail for a perfect example of how it should be done.