The Address Book icon is in your Dock, your Applications folder, and in the Mail “Compose” toolbar.
The Address Book works both independently and with Mail to create Address Cards that store contact information for individuals or groups. When Mail is open, you can automatically create an Address Book entry for anyone who sent mail to you. When Address Book is open you can automatically address email to an individual or group. You can search the Address Book by name, email address, or by a user-defined Category.
The “card” ...