In this video for Mail on the Mac, I show you how you can set the number of lines of preview you see when looking at all your mail messages in a list. You can set Mail to show none or now preview. This will then show more mail messages in your list. But you can also show up to 5 lines of preview text for each mail message in your inbox. See how to change how much of a mail message is shown as a preview in this lesson for Mail on the Mac.