Most UNIX users are very comfortable with statically linked libraries (e.g. libXXX.a). Most are aware of ``shared object files'' in UNIX (with the form libXXX.so) though few actually build them. Even fewer still are familiar with dynamically linked libraries, called DLL's in Microsoft (after the common .dll suffix), which involve actually selecting and loading dynamic libraries at run time based on their string name. This section serves as a quick overview of how Babel handles both static and dynamic libraries, including runtime loading.