This is a great book that profiles the life of Spaniard Manuel Lisa and how he virtually started the Upper Missouri fur trade.
You get all the details on this man's life, including the time when the fur trade was "dead," 1814-1819. Lisa was quite active during that period.
If you want more than Wikipedia has to offer, this is the book. Wow, I'm surprised by how much stuff there is about this man. Can't wait to write more about him!