This chapter contains most of the original text, although with a few tweaks. There are two big additions which I did not cover in the first edition of this book.
I added a section on security with the DBI module and SQL injection. I don't really think it belongs in this book any more than any other sort of problem with a CPAN module, but enough people complained that I relented.
And, I added a brief introduction to the Safe module. This is a rarely used security feature that you might find useful if you have to use string eval.
I've added some of the sample programs to the downloads page.
You can read the draft chapter now.