The authors are Frances Widdowson and Albert Howard and the subtitle is The Deception Behind Indigenous Cultural Preservation. Here is one good two-sentence excerpt:
The "evidence" from "oral histories" is even more problematic when economic interests are involved. Oral histories have been known to change when a claim is necessary to obtain access to valuable resources.
This book is too polemic for my tastes and it doesn't try hard enough to understand the other side of the issue. But it makes many very good points backed up by many very real examples. It is strongest when arguing against the lowering of intellectual standards for arguments made on behalf of indigenous groups.