Make Phone Call While Reading Mail

[Android Question]

I imagine that this question has been asked man times (Galaxy SIII), but if I am reading my email, let's say that I just remembered that I need to call someone.

How can I make an outgoing call without closing down the mail, and jump over and make a call? If I hit the back button (the curly arrow in the lower right), it closes the mail that I am reading.

 

[Rukbat]

Press the home button. Make the call. Finish the call. Long-press the home button. Choose the mail app. That's how Android simulates many open windows on a desktop.