You can preview items in your Inbox without opening them by using the Reading Pane — just click the message to display the text of the item. In the Reading Pane, you can also open attachments, follow a hyperlink, use voting buttons, view the follow-up information in the InfoBar, and respond to meeting requests.
Security Note: You can view messages safely in the Reading Pane. Potentially malicious scripts or attachments are not activated or opened automatically in the Reading Pane. Although most malicious attachment types are blocked by Outlook, messages and attachments from unknown or unsolicited senders should always be treated with caution.
What do you want to do?
Turn on the Reading Pane
On the View menu, point to Reading Pane, and then click Right or Bottom.
Turn off the Reading Pane
On the View menu, point to Reading Pane, and then click Off.