Main Menu: Edit -> Address Book
The Address Book is divided in two parts: Personal Address Book and Automatically Collected Address Book. Each part has its own list of addresses. The only difference is that the addresses in the Personal Address Book were added manually, or were added automatically when you received a RSA Public key from somebody, but the addresses in the Automatically Collected Address Book are added automatically when you send an email to somebody that has not an enter in the Address book.
Click on any of the two buttons on the top left (one with an A and other with a P letter) to switch between both address books.
You can add, delete. move and clone items in the Address Book.
The Clone buttons create a duplicate of the selected contact. The Move button only is active in the Automatically Collected Address Book because its only function is to move contacts from that Address Book to the Personal Address Book.
If you select an item and click the Edit button, the Edit Contact window will appear.
Besides obvious text box, each contact can have one or more email addresses. If the contact already sent you its RSA public key, it will appear in the RSA Public Key text box.
Notice that, by default, when a contact has a public key, the Message Encryption option enabled is Ask for each Messages. That means that every time you send an email to that contact, the program will ask you if you want to encrypt it.