Earlier I posted an item on how to interpret email headers.
Here is an interesting article about the email headers — metadata.
Tresa Baldas, Metadata Grows in Legal Import, The National L. J., 26 January 2009.
In cases where the prosecution evidence consists of emails, metadata may be very helpful to you. I recently had a case where a unhappy wife was creating and sending ficticious emails to the client and others. Metadata can tell you a lot including such simple things as IP addresses, MAC addresses, and other information that can help track down the computer from which the email was sent. Your computer, this computer I'm typing on, has a unique address, the MAC address, for example.