In Atlantis you can have one or multiple address books. An address book in Atlantis is a collection (a list) of postal addresses. Each of these addresses has its title (a name). Addresses should have titles which clearly identify the address itself so that you can easily locate any required address among the available addresses. For example, if your address book contains your home address, "My home address" would be a good title for this address.
Address books are used in Atlantis mainly for creating envelopes. They are very convenient for printing envelopes for bulk mail (in this case address books work like lists of delivery addresses).
The Atlantis address books are ordinary text files with the ".txt" filename extension. The first line of the address data is always the "address title" identifying the particular address uniquely:
The address itself is written right below its "title" or label:
The addresses themselves are separated by one or more empty lines:
You can create new address books, remove or modify existing books by clicking the "Address Books..." button on the "General" tab of the "Tools | Options..." dialog. Being ordinary text files, the Atlantis address books can be also edited manually in any text editor or word processor. Do so if it feels more comfortable to you. But be sure to adhere to the "title+address+separating line" format as described above.
You might want to have different address books for different groups of people. You could create a "My Relatives" address book, a "Golf Club Members" address book, a "Business Contacts" address book, etc, etc. For example, creating a "My Friends & Relatives" address book would help you create and print envelopes to send Christmas cards to all of them at once. The "Golf Club Members" address book could be used to create and print envelopes to send invitations to a Golf Tournament. Etc.