Sitchin's books are always a pleasure to read with the author's engaging style and bold assertions, but the most obvious hole in his theory is that there is NO evidence of any cataclysm or upheaval in 100BC when Nibiru was supposed to have passed the earth according to the author's own chronology. He claims it comes by every 3600 years and that it caused the great upheavals and the end of the last ice age in about 10 000 BC. Also, he makes stupid statements about linguistic affinity and does not work like a scientist here. It is easy enough to find similarities between a language in Eurasia and one in the Americas, but one must put this in context, in a broader taxonomy (classification structure). There are similarities between Sumerian and Nostratic (Eurasiatic) the parent family of Indo-European and many others, and also (other)similarities between Sumerian and Dene-Caucasic. For these, I recommend the work of professional linguists like Alan Bomhard, Joseph Greenberg and Merritt Ruhlen. Sitchin takes many liberties but at least he does it in an entertaining way.