Expert systems (ESs) attempt to duplicate the work of human experts by applying reasoning
capabilities, knowledge, and expertise within a specific domain. They have become valuable
in many application areas, primarily but not exclusively areas involving decision making. For
example, navigation systems use rules to select routes, but we do not typically think of these
systems as expert systems. Significantly, expert systems can operate as standalone systems or be
embedded in other applications. We examine ESs in greater detail in Technology Guide 4.