CaBook extends Outlook's address book manager with custom actions which can add the message sender's and recipients' information to the address book - either to the contacts folder or personal address book.
The first thing you'll have to check is that you've installed the Rules Wizard to MS Outlook or you're connected to MS Exchange Server. Once installed, CaBook features an address book manager which allows you to store the message sender's and recipients' information to your Outlook address book or remove them from it. This address book can be either Outlook's Contact Folder or Personal Address Book. In the case that you use Outlook's Contact Folder, you can set categories and a comments field. The problem is that it doesn't seem to synchronize very well with Outlook's own address book - it boils down to a case of using one or the other. However, CaBook is much more advanced in the features it offers giving you more scope to add details about contacts.
CaBook is a nice idea although if it worked better with Outlook's own address book, it would be much less confusing.