mail in snow leopard - hidden address database?

In Mac Mail, when you type an eMail address in the To: field, do the entries get saved to a "hidden" database that you cannot access directly?

The reason I ask is, on my Dad's MacBook Pro,when you start typing in the To: field a bunch of addresses are being found as you type that are not listed in the Address Book, including some incorrectly formed eMail addresses that I end up having to delete one by one manually in order to prevent errors when sending mail.

I can always just disable auto-completion, but my Dad likes that feature. I could also tell him to use the address book to create new mail, but he doesn't want to do that either.

I'd really much rather be able to access this entire "hidden" database of saved addresses, and/or perhaps force the software to use only addresses in the Address Book when auto-completing as you type.

 

Excellent. Thanks very much.

It would also be nice to be able to set a preference to use only addresses in the Address Book for auto-complete. Perhaps, as a work around, I can set a preference to not store addresses typed into the To: field?