If the sender included a Display Name eg: BobJob <BJ@address> Then the 'From' will display the Display Name eg: BobJob If the sender did not include a Display name - just the email address: eg: BJ@address Then the 'FRom' will display the email address. If you have settings in Options to 'Show only display name for people in my address book' Then it will show whatever 'Display' you have set up for that contact details in the Address Book. So for contact Bob Job, under 'Display' you typed: eg: Bro Bob Then you will see 'Bro Bob' in the 'From'. So if you actually enter the contact with the 'Display' containing the name and email address, then that is what you would see in 'From' . However, this does not help if person is not in the address book. You might find this addon useful. It allows you to have another column header - eg: Sender * https://addons.thunderbird.net/en-US/thunderbird/addon/full-address-column/ * https://support.mozilla.org/en-US/kb/installing-addon-thunderbird