This document provides information about CPAN (Comprehensive Perl Archive Network) including what it is, how to use it, popular modules, authors, and tips. Some key points: - CPAN is a repository for Perl modules with over 12,000 modules and 3,400+ authors. It helps avoid duplicating code. - Popular ways to install modules include using the CPAN shell, CPANPLUS shell, or cpanminus command line tool. - Useful modules cover areas like web development, databases, testing, graphics, and more. Top authors contribute many modules. - Documentation for any module can be found via its perldoc or on search.cpan.org.