What is the author's style in Personal Memoirs of U.S. Grant by Ulysses S. Grant?

The book was Grant's "personal memoirs". As such, it was written exclusively in first person. The perspective was entirely limited, as is appropriate for a memoir. Grant told the story of his life, relating incidents from his childhood through adulthood, including his term as leader of the Confederate Army. The fact that the perspective is so completely limited means the reader has to beware of Grant's personality and prejudices. The reader must also keep in mind that details were presented as Grant's memories. It's possible that some details were skewed because his memory was faulty. It's also important that the reader remember that details Grant placed great importance on may not really be that important. For example, he related the story of being ridiculed by other boys for making a poor deal in purchasing a horse. It seems possible that he remembered the teasing as more important than it really was. Other events related throughout the book may by similarly distorted and it's left to the reader to decide the importance of each. In one case, Grant mentioned the battle of Shiloh and said that it was "more persistently misunderstood" than any other Civil War battle. The reader has to decide whether Grant's interpretation of the events was more reliable than other historians and other accounts.