\chapter{Introduction} The Python library consists of three parts, with different levels of integration with the interpreter. Closest to the interpreter are built-in types, exceptions and functions. Next are built-in modules, which are written in \C{} and linked statically with the interpreter. Finally there are standard modules that are implemented entirely in Python, but are always available. For efficiency, some standard modules may become built-in modules in future versions of the interpreter. \indexii{built-in}{types} \indexii{built-in}{exceptions} \indexii{built-in}{functions} \indexii{built-in}{modules} \indexii{standard}{modules} \indexii{\C{}}{language}