Go to Tools>addressbook, highlight the book, righ-click and select export.

Thank you!!

Upon examining the export file it does not contain all the fields that appear in TB. Especially noted absent is the second home address. How do I get it to export all fields that appear in TB?

If it is not exporting everything, then there is a bug. You can report that at this URL: bugzilla dot mozilla dot org.

Need a bit more steps to how to report bug. I tried the URL and it links me to another site that seems not Mozilla and wanted me to create an account..not sure I am doing this correctly. Is there step by step instructions somewhere on this Mozilla support site you can direct me to?

This is the place: https://bugzilla.mozilla.org/home Once you create an account, there is a place to open a bug report.

Thank you..I created an account and reported it correctly I hope!