I wish I had read the negative reviews more closely. This is not a book, it is more like a pamphlet with some information about the Sumerians, without maps, illustrations, listed author(s), page numbers, edition/print information, sources, bibliography, etc. It doesn't have a Library of Congress entry, or any other information that could give a clue of who wrote it. Reading Wikipedia would have been more informative and free. The "book" even lists Wikipedia as the source of the cover photo.
It contains exceedingly dubious statements, such as that the word "legal" comes from the Sumerian "lugal" while in fact comes from the Latin "legalis". Then it bring up the far-fetched possibility that the Sumerians could have been extraterrestrials, presented on pretty much equal footing with any other theory about their origins. This is a completely useless "book".