This is a most interesting book and one that I will probably have to read again.
Harsh Mahaan does indeed interpret the Vedas in an interesting manner and does provide us with some alternate histories of the Aryans.
He postulates that their story started from the Arctic Circle. While I do not claim to be an expert, I wonder if this interpretation is correct. He postulates that Indra, Manu, Yam(a) etc were kings and warriors of old, who gradually were deified. I do think that this is a possibility. I also think that there is a possibility that they were blonde, as he has suggested.
Since the journeys were, as seen from our times, obscure and sometimes difficult to understand, I would have liked that the chapters were to be broken down into sections. A 'family tree', even as a postulate, and maps, would have helped to make the narrative clear.
It is indeed a book well worth reading. It is a book that needs a second, clearer, edition.