I would like to know how to read and understand email options

For which e-mail client or service?

When I receive emails, in Outlook 2007, I go to "options" and would like to understand where it comes from exactly. There are many lines...

Thanks for your help.

Ahh you are trying to understand the header of the e-mail? May I ask why?

Exact... because I like to understand... I am more or less in computer science, and sometimes I receive weird emails. Is it so strange? :). I have already seen that there are sites explaining, but I have forgotten which ones, and many times sites explaining things are not very clear.