Have you recently discovered Native American roots in your history? Tracing those roots can be difficult. Depending on which tribe your ancestors belonged to there may be virtually no records earlier than the 1880s. Early Native Americans were not taxed, therefor they were not included in the U.S. Census.
With some tribes, the U.S. Government required anyone trying to claim a portion of the monetary judgment to prove their ancestry back to 1838. Many other nations, such as the Navajos, did not even speak English until the 1950s and 1960s. Reading the few records they had would be difficult and if the histories weren't passed down then as children lost interest in their family roots, the ancestry roots could be impossible to find.
Your best information sources are usually through family records; Family Bibles, journals or passed down history and stories. Remember, you are the researcher; so find as much information as possible before you contact the Indian Bureau. They do not have the time, ability or funds to do the research for you!