This is Perl module Devel::MRO. INSTALLATION Devel::MRO installation is straightforward. If your CPAN shell is set up, you should just be able to do $ cpan Devel::MRO Download it, unpack it, then build it as per the usual: $ perl Makefile.PL $ make && make test Then install it: $ make install DOCUMENTATION Devel::MRO documentation is available as in POD. So you can do: $ perldoc Devel::MRO to read the documentation online with your favorite pager. Goro Fuji