I've read a few books on the manufacture and testing of black powder. I thought it might be useful to post a few resources for those interested in gaining a more in depth knowledge on the subject. This is a great book that you can download for free. I'll start with this one, and if you guys want more I'll provide more. Just let me know.
This one is by Ian von Maltitz, it's titled the "The Manufacture Testing and Optimizing Black Powder".
http://pyrotechnic.narod.ru/Black_Powder.pdf
Just download it at the link provided.
In return, I ask that anyone that has a good link, or perhaps a title or author worth reading, that they post that information here as well. I'm always interested in learning more.