Step-by-Step Tutorial for Writing Advanced Batch Files

Though Dr.Batcher allows everyone to create batch files without having any knowledge in this area, we are asked sometimes about step-by-step lessons on batch files creation. Of course we are thinking of writing such tutorial, but that's long time matter. So here are some links on tutorials created by other people.
You can find a really good lessons on batch files at http://www.allenware.com/icsw/icswidx.htm. The set of lessons start with learning ECHO command and environment variables, then it describes using child shells, continues with lessons on ERRORLEVEL, working with files, debugging batch scripts and so on. Every lesson is coherent and well-illustrated.I should say that I consider these lessons to be useful even for those people who are familiar with batch files. Why? Because sometimes it is useful to refresh your knowledge and find something new in usual techniques