I too found that biography to be very entertaining and informative. It was interesting how Grant spent the last several months of his life writing for most hours of almost every day. He dove into it, and apparently gave Twain's publishing firm a pretty good product that they could easily work with.
Grant was a very skilled man throughout his life in regard to arithmetic, equestrianism, and military arts among other things. However, he truly found a new skill and passion in writing while literally on his deathbed.
i think that the concensus is that grant did it to ensure support for his wife after his death, which to me shows that he was very good man (and his actions in the civil war, and after, back this up).
i've read about half of his book, which can be quite funny in places. but relies (naturally) on some detailed appreciation of the geography of the battlefields, and geography has ever been my least favourite area of knowledge, so i had to give it up.
That's interesting, he must have had a great mind for visualizing geography, as evidenced in part by his detailed description of it in his accounts years later. That mixed with his logistical expertise (he was a quartermaster in the Mexican War) would make him a very formidable general.
Grant was a very skilled man throughout his life in regard to arithmetic, equestrianism, and military arts among other things. However, he truly found a new skill and passion in writing while literally on his deathbed.