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) -- but 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 (based on their string name) at runtime. This section serves as a quick overview of how Babel handles both static and dynamic libraries, including runtime loading.