Add them to what?

If you open a message, there is a grey bit at the top which has the sender, the date and time and so forth. If you click on the sender's name, in Thunderbird you should get a pop-up which amongst other things allows you to add that name and address to your Address Book. Would this be what you're looking for?

Note that there is a star next to each of the various addresses. White (empty? silver?) means it isn't in your Address Book, and yellow (gold?) means you already have it. If you click a gold star, you get an option to edit that address book entry.

DavidJE mentioned this in another unconnected and closed thread question instead of posting some info in the actual question - so I've copy pasted the response query.

For example I asked how to automatically add incoming e mail addresses (to my addresses) but was only told how to do it manually, one by one.

You did not specify your needs - you asked: How do I automatically add chosen incoming e mail addresses.

It has been assumed that you wanted to auto add an incoming email address to an address book without needing to open up Address Book and manually add the contact. The info given precisely answers that question.

New Email addresses that you use to 'send' an email that are not in your Address Book, can be auto added to the 'Collected Addresses' address book or another of your choice upon sending email.

'Menu icon' > 'Options' > 'Options' > 'Compositions' > 'Addressing' tab see image below.

• select checkbox: 'Automatically add outgoing email addresses to my:'
• Select an address book of choice.
• 'Collected Addresses' is usually set as default, but you can choose another.
• Click on OK

There is an addon you could try, but I've not used it.

It has been around a while:

• https://addons.mozilla.org/en-GB/thunderbird/addon/email-address-crawler/

Info on how to install addon:

• https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

You can have all incoming addresses automatically added to an address book, but it can't be done automatically for a select, or 'chosen', set. To accomplish the former, use the Incoming Address Collector add-on, which is similar to the Email Address Crawler add-on mentioned above.

To add the addresses of select incoming emails, in a semi-automated way, you could create a filter that automatically copies messages to a folder, based on certain criteria, and then manually run the Crawler add-on on the folder.