While setting up my parents’ new business computer, my mom expressed her wish that Thunderbird would sort the contacts by last name instead of by first name and display their names in the format Last, First. I couldn’t find an option in the GUI for this, but after doing a little digging in the Config Editor and some research online, I found the answer.

1. Click Tools -> Options
2. Click the Advanced “tab”.
3. In the filter box, type lastnamefirst.
4. Double-click mail.addr_book.lastnamefirst
5. Change this value to one of the following options:
   • 0 – display the “Display Name” value as the contact’s name.
   • 1 – display Last Name, First Name as the contact’s name.
   • 2 – display First Name, Last Name as the contact’s name.
6. The change should be noticeable in your address book immediately.

Note: This is applicable for Thunderbird 1.5. I do not know what sort of support for this option will be provided in future versions of Thunderbird.