I have multiple Contacts folders but only 1 shows up in the Address Book.
How can I add the other folders?
Right click on the Contacts folder that you want to add to your Address Book and choose Properties. Here select the tab Outlook Address Book and select the option "Show this folder as an e-mail Address Book."
Outlook Address Book tab in the Properties dialog of a Contact folder.
Shared Contacts and Public Folders
You cannot add a shared Contacts folder of a manager, or somebody else who has shared his/her Contacts folder with you, as an e-mail Address Book.
In order to add a Public Folder Contacts folder, you’ll need to mark that it as a Public Folder Favorite first.
Note: For issues with the Address Book, also see; Contacts are not available in the Address Book