I'd suggest you think about how others might use this data. If I were to be given a text list of email addresses I'd be disappointed because it's likely that the only way i could use them would be to laboriously copy them, typing by hand, into my own address book.

The most commonly used format for moving address book data around is the CSV file. Thunderbird and just about any other email client can export and import this format. Look under Tools in the menu in your Address book.

The CSV file will have one line per Contact, and when viewed in a spreadsheet, will have the data organised into columns, so it's quite easy to trim out irrelevant or expired data. If you don't have a spreadsheet there are free programs, such as Google Docs (online), or Libre Office which you download and install on your own computer. Google Docs is probably easier to learn.

The most natural export "unit" is an address book, e.g. Personal Address Book, or Collected Addresses. If you're using a Mailing List then you might have to export its parent address book and remove all the unwanted Contacts from the CSV file, or look to the MoreFunctionsForAddressBook addon for Thunderbird which enhances the import/export options available to you.

Thanks very much Zenos

From your answer the CSV file seems to be just what I need.

My remaining problem is how to make Thunderbird export a CSV file. I have looked all over the various tabs and tools in Thunderbird itself and in the Address page without finding an Export facility.

I will have no problem with a spreadsheet. We have other uses for such a file than importing it into another email system such as someone other than me checking it off against our membership list.

Incidentally I have found that Thunderbird will accept Ctrl-V from a .txt file to create a new list. That's how I created the list in the first place using a list I have now out of date.

Unfortunately there is no menu including "Tools" in the address book I am looking at.

Open the Address Book, use F10 or alt+v to make a menu bar appear. In that menu, go to View|Toolbars and tick the checkboxes.

I am afraid the developers have really messed up Thunderbird. They took away the conventional menus and replaced then with the "hamburger button", yet this button isn't available in all the windows. So even if you like the wretched hamburger button and its menu (I don't!), you can't easily use it in the Address Book, or the Composition window, or a standalone Read window.

Inconsistently, in the Calendar you can add the hamburger button.

Bill_Fisher said

Incidentally I have found that Thunderbird will accept Ctrl-V from a .txt file to create a new list. That's how I created the list in the first place using a list I have now out of date.

I think that you were lucky that the pasted text was in a format that Thunderbird could understand. ;-)

Once again thanks very much. You have solved a problem I have been struggling with for months. I have tried it and it does just what I want. Who would possibly have guessed that to see a menu you have to use F10?

On the question of pasting from memory what I did was create the mailing list and then edit it using a Ctrl-V paste to load all the entries. I did the same today with another new list pasting the list from the To: section of a source view of an email someone had sent me and the others I wanted in the new list. I then manually removed the commas. It seems to have worked.

Thanks once again Zenos for your valuable help.

https://support.microsoft.com/en-gb/help/126449/keyboard-shortcuts-for-windows

Same F10 shortcut works in Linux too. Seems to be a well-established convention.