The first bit of advice I have is not to start in the Address Book. ;-) Start with Forward, and the message will open in a Write window. In principle, you just use the Mailing List's name as if it was an email address. So you can add it to any message open in the Write window in the usual ways: 1) start typing into an addressing box and autofill completes for you, or 2) use the Contacts Sidebar and add it from there. In both cases, I'd suggest you use Bcc: to avoid copying all of your correspondents' email addresses to one another. The Contacts Sidebar can be switched on and off using F9, or via the menu, '''View|Contacts Sidebar''', and you can add it to the Write window's toolbar. '''View|Toolbars|Customize''' No menu? No toolbar? Press alt, then V for view, and tick the boxes. If you add the Mailing List to your message and TB complains about it not being a valid email address, check both its name and description for spaces, and replace them by underscores or similar. Avoid anything quirky like question marks, slashes, ampersands, brackets, etc too.