Regarding historical pharmacology, I am working on getting a copy of the United States Dispensatory. There are snakeoil salesman and as such I do my best to educate myself for my customer's sakes. My sole piece of advice is to not buy anything over the radio but ask me first because I always find something cheaper and better quality. Plus I cross check with drug references,etc.
If you like to read, get 'Back to Eden' by Jethro Kloss.
What's that?
Never mind. I googled it. That looks like a great idea. It's amazing how much they knew back then. Have fun. Think I'll check it out further when I have the time.