FRom what I'm seeing the book may be Seven Myths of the Spanish Conquest Matthew Restall
it was definitely him that wrote it. I found the section of the podcast again though McCann doesn't mention a book I think.
He also mentions a couple of other books The Other Slavery: The Uncovered Story of Indian Enslavement in America
by Andrés Reséndez and one by a female author which I need to find again also looking at slavery. Managed to note the names down as I was walking around town this time.
― Stevo, Wednesday, 31 May 2023 19:27 (eleven months ago) link