This is a copy of a comment I made a few weeks ago over in r/indiancountry.

While not written by native authors this list might help you. These are a few of the books I have that provide glimpses into the lives of the Indians written by people who witnessed it first hand. I also have a huge stack of journals and chronicles taken from the early fur traders where they wrote brief observations of the events they witnessed.

Frederick Drimmer Captured by the Indians: 15 Firsthand Accounts, 1750-1870

Elijah Nicholas Wilson The White Indian Boy:: The Story of Uncle Nick Among the Shoshones

John Rodgers Jewitt White Slaves of the Nootka: The Adventures and Sufferings of John R Jewitt While a Captive of the Nootka Indians 1803-05

John Dunn The Oregon Territory, and the British North American Fur Trade: With an Account of the Habits and Customs of the Principal Native Tribes on the Northern Continent

Margot Mifflin The Blue Tattoo: The Life of Olive Oatman

Herman Lehmann Nine Years Among the Indians, 1870-1879: The Story of the Captivity and Life of a Texan Among the Indians

James Adair The History of the American Indians

Peter Skene Ogden Traits of American-Indian Life and Character

Scott Zesch The Captured: A True Story of Abduction by Indians on the Texas Frontier

J. W. Schultz My Life as an Indian: The Story of a Red Woman and a White Man in the Lodges of the Blackfeet

Peter Erasmus Buffalo Days and Nights

Daniel Williams Harmon A Journal of voyages and travels in the interior of North America, between the 47 and 58th degree of North Latitude. To which are added a concise ... face of the country, its inhabitants, etc