Title: New Developments on the Formal Ball Domain Jimmie Lawson Abstract: The formal ball domain has proved a useful tool for modelling metric spaces for computational and other purposes. After a quick overview of its basic structure and properties, we consider the problem of determining those metric spaces for which the formal ball domain is an FS-domain. We also consider the extended formal ball domain, which is constructed by allowing formal balls of negative radius, and survey some recent work pertaining to it.