You'll have to buy a copy. I bought one maybe 15 years ago, and at the time it was out of print. It's a good read, not difficult.
The biggest takeaway for me was that a society that doesn't believe it is superior, is doomed to extinction.
“The biggest takeaway for me was that a society that doesn’t believe it is superior, is doomed to extinction.”
I read that Geronimo believed to the end that the Apache way was superior.