misdelivered; normally, you can safely ignore it. Headers also often contain useful stuff like a time and date stamp and an indication of whether files are attached to the message.

The three most important pieces of information in the header are the email addresses of the sender and the recipient, and a subject line that tells what the message is about. All email messages -- whether or not they travel over the Internet -- contain these three pieces of information.

When you send an email message, your return address usually appears automatically. You just need to fill in the "To" line (with the recipient's email address) and the "Subject" line (with a clear and concise description of the subject of your message).

The Internet addressing scheme

ms.netiquette@albion.com

The "ms.netiquette" part is my "handle" -- my Internet nickname. "Albion," the organization name, refers to Albion Books, my publisher; and "com," the domain designation, means that "Albion" is a commercial business. There are six major Internet domain designations:

• com commercial businesses
• edu educational institutions
• org nonprofit organizations
• net networks
• mil the military
• gov government entities

President Bill Clinton's Internet address is president@whitehouse.gov. Vice President Al Gore's is vice.president@whitehouse.gov. They both welcome email suggestions. Go ahead -- give it a try!

Other addressing schemes

Each commercial service and mail system has its own addressing scheme. For example, on CompuServe, people don't have "handles."