This feature requires you to be using a Microsoft Exchange Server e-mail account.

1. In Mail, on the Tools menu, point to Send/Receive, point to Send/Receive Settings, and then click Define Send/Receive Groups.
2. In the list, click the group you want, and then click Edit.
3. Under Accounts, click your Exchange Server account.
4. Select the Download offline address book check box.
5. Click Address Book Settings.
6. Under Information to download, click Full Details.

   Note  Downloading full details is not recommended unless you have a high-speed local area network (LAN) connection. An Offline Address Book can potentially be several hundred megabytes (MB) in a large organization.