Clicking on the Address Book link anywhere in the messaging system will bring you a customized address book generated just for you. This address book automatically grabs your fellow group members and people you have recently been in contact with through the messaging system. By holding down the control key (PC) or the command key (Mac) you can select multiple users in this book to send a message to. When you press the Add button the recipients you selected will automatically be added as receivers for a message.