I had forgotten about this book but I've spent the day cleaning out my hard drive and found it. Anyone that wants to understand the relationship between slavery and capitalism need only read the first 5 chapters. You can also see how some of the principles still apply today.
http://archive.org/download/capitalismandsla033027mbp/capitalismandsla033027mbp.pdf
http://archive.org/download/capitalismandsla033027mbp/capitalismandsla033027mbp.pdf