The address book is a place to store your commonly used email addresses. You can call up the address book from the File menu, the address book button on the Main window, or the address book button in the Composer window.
To add addresses to the address book, type an email address into the lower section of the window and hit the Add button. The address will then appear in the list. To remove an address, select it from the list and hit the Remove button.
Addresses can also be added to the address book from the Mail Reader window by right-clicking on an email address in the To: or From: fields and selecting Add to address book.