Reddit reviews The Wolf at Twilight: An Indian Elder's Journey through a Land of Ghosts and Shadows

Some suggestions:

Oral History/Stories

• The Sons of the Wind: The Sacred Stories of the Lakota - Dooling
  
  
• American Indian Myths and Legends - Erdoes, Ortiz
  
  
• American Indian Trickster Tales - Erdoes, Ortiz
  
  Historical/Educational material
  
  
• Letters and Notes on the Manners, Customs, and Contitions of North American Indian; Vol. I & II - Catlin
  
  
• Major Problems in American Indian History - Hertado, Iverson
  
  
• We are Still Here: American Indians in the Twentieth Century - Iverson
  
  
• American Indian Politics and the American Political System - Wilkins, Stark
  
  Native Authors
  
  
• Custer Died For Your Sins - Vine Deloria Jr.
  
  
• Standing in the Light - Young Bear, Theisz
  
  
• The Way to Rainy Mountain - Momaday
  
  
• Prayers of Smoke
  
  
• Bury My Heart at Wounded Knee: An Indian History of the American West - Brown
  
  Non-Native Authors
  
  
• Neither Wolf nor Dog: On Forgotten Roads with an Indian Elder - Nerburn
  
  
• The Wolf at Twilight: An Indian Elder's Journey through a Land of Ghosts and Shadows - Nerburn
  
  
  Region Specific
  
  
• Lakota Society - Walker
  
  
• The Lakota and The Black Hills - Ostler
  
  
• Black Elk Speaks - Neihardt
  
  And just for fun, a Movie
  
  
• Dreamkeeper - Steve Barron
  
  Feel free to point out any mistakes, I'll add more should I think of them.
  
  These are just suggestions.