Specifically, what major contribution(s) has the Bureau of Indian Affairs (BIA) made?

Answer 1

http://www.jiskha.com/search/search.cgi?query=Bureau+of+Indian+Affairs
Here are many posts and responses about the BIA. You should find interesting information in here.

http://en.wikipedia.org/wiki/Bureau_of_Indian_Affairs
This may help, too.

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