1. Thunderbird for Android does not have address book of its own, and Thunderbird for Android can use the address book of your Android phone. The following link might be helpful: https://support.mozilla.org/en-US/questions/1484999#answer-1702948 2. You can post your feature request in the following forum: https://connect.mozilla.org/t5/ideas/idb-p/ideas/label-name/thunderbird%20android There is already the same feature request in the above forum, and you can upvote it: an address book in Thunderbird for android https://connect.mozilla.org/t5/ideas/an-address-book-in-thunderbird-for-android/idi-p/84952