We recently moved from an ISP email situation to Exchange 2010. The server is running Windows Server 2008 R2 Standard with Exchange 2010. The former setup included .pst files for each user. When we switched to Exchange we imported the .pst file to each user's account. The problem relates to one user adding a new email contact that is not propagated to all the other users. So I believe we would require a "Global Address Book" for all users to be able to access. Right now there are two address books for each user - the regular "Contacts" and the company's address book. What would be the best way to make this work?