As an accomplished author, David writes about the the mountain men of the American west and other periods of early American history. He has published two books, Rocky Mountain Destinies and Purple Rains. Rocky Mountain Destinies was published as a single book, Purple Rains contained both Rocky Mountain Destinies and Hidden Treasures in one volume.
While Rocky Mountain Destinies and Hidden Treasures is currently out of print, Purple Rains, a compilation of both books has just been released. You can order the book directly from the Purple Rains website.