What do you have to start with?  If you have a data source, use that with
mailmerge to create a catalog (or in Word XP and later it is called
directory) type mail merge.  In the main document, just put one set of the
merge fields in the configuration that you want them and then execute the
merge to a new document.

What sort of an address book? Microsoft provides Outlook for this, which is
the only address book that interfaces directly with Word. You could create a
table that contains your addresses, one per row, which can be used as a data
source for mail merge, but that's about as useful as it gets.