If you find a message wrongly classified as spam, you can unmark the message. Just select the message and click the Not Spam button that appears at the top and bottom of your list of messages. Unmarking a message will automatically move it to your inbox. If you find that some senders' messages are consistently being mislabelled as spam, you can prevent this by adding their email addresses to your Contacts list. Gmail will deliver messages from members of your Contacts list to your inbox.