Email messages, as in the case of their non-electronic cousins, have "envelopes" of a sort. In the case of email the envelope is composed of a series of "Headers". These are just a series of lines of characters which precede the actual email message. Email programs such as Outlook do not normally display these Headers when displaying a message. From these Headers however, the email program is able to extract important information about the message, such as the message encoding method, the creation date, the message subject, the sender and receiver, etc.
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