If you write any software package, you have to document it. This simple truth drives more than few developers into despair. But there is also a way to craft good documentation and make the writing of it a useful part of the development. This is the closing part about authoring a Perl 6 module and Math::Matrix in particular (part: one, two, three, and four). iPOD Since Perl 5.0, we have been able to use a markup language called Plain Old Documentation, that can be embedded into code. Since Perl 6 is a complete overhaul, the power of POD was also extended. One of the most interesting expansions is the metamodel-method HOW that can recall the documentation associated (written in front of) with a routine (sub or method). However, I did not use this feature yet, because this topic contains math that requires much longer explanations and examples than I would not want to see as a quick help output in the shell. I plan to supply these kinds of docs later, as a summary of the well-rounded documentation we will have then.