You are correct and there are experts who specialize in this science. A skillful writer might be able to fool one for a couple of paragraphs or even a short article. But not with something of book length.
I read about this before the election. I thought the scientific evidence was pretty damning. Obama had not written anything of substance until that book.
Obama and Michelle stayed in BALI for 6 months so that he could write it without interruptions.
I thought that was really odd. Why not hole up at home? It would be great to investigate if Bill was in Bali during the same time.