The part about Argentine Tango is okay, but certainly not great. No footnotes from the book he used or anything. Try this also http://www.todotango.com/
check out the link to chronicles, origins of Tango
Thanks for the links, will. I've found that a lot -- these compilation history pages give an overview of lots of dances, but perhaps not enough in-depth information for any one. I'll check out the links!