"The photographs are taken from the 20 portfolios and 20 encyclopedic volumes of the work entitled "The North American Indian" by Edward Sheriff Curtis, published between 1907 and 1930"--Title page verso.
Translated from the German.
OBNB doesn't sell books, but you may be able to find a copy at one of these websites:
The North American Indian : the complete portfolios by Edward S. Curtis. ISBN 9783836550567. Published by Taschen in 2015. Publication and catalogue information, links to buy online and reader comments.
