Think of your address book like a telephone book. Normally, phone listings are grouped logically, by town or district area. How much more difficult it would be if the entire state/province was combined into only one big list. You can move contacts from one list to another, if you wish. Left-click and drag a contact to the Directory Pane and drop the contact onto a different book. You can even 'select all' drag and drop. Thunderbird has a default 'All Address Books' which is a virtual book that contains all contacts from every book. Isn't this what you wanted to do. You can add a column to the contact list pane to show the 'Address Book' that contains the contact's entry. TB-38.2 Win10-PC