I have enjoyed all of Keegan's books – The Face of Battle was so good that I started reading it out loud on the first page simply because the prose was so outstanding. This one analyzed command from the perspective of Alexander the Great, the Duke of Wellington, Ulysses S. Grant, and Adolf Hitler. I learned a lot that I did not know previously about all four, but I found it irritating that he makes such categorical statements about events with regard to Alexander, since what we know about him is so second and third-hand. It may in fact be correct, but don't think historians are describing events correctly when they describe something that is so distant in the past that we really don't know for certain what happened – just what is reported to have happened or what later riders said had happened.
However you really don't have that problem with the Duke of Wellington, and I enjoyed that section enormously. The section on Grant was a little thin, especially given that we know so well exactly what he was thinking as a result of his tremendously detailed and enlightening biography. The final section on Hitler was very, very good. Keegan provided a detailed overview of Hitler's service in the trenches in World War I which gave me new insight into why he was able to bully his generals so effectively – he had faced extreme danger in the trenches in the prior war, and the generals had come nowhere close. As a result, he inserted himself into tactical decisions and believed he understood what was happening on the front lines better than his generals. While he might've been more familiar with what the front lines were like than they were, he was in no better position to contradict his generals in this war, and in fact considerably worse off in terms of his understanding of what was actually happening. But the description of what daily life was like around his headquarters was very interesting.
Keegan finishes with a analysis of leadership in the nuclear age which to me was hard to relate to the prior subjects in the book, and also made the again somewhat irritating claim that everything is different now from what has gone before, which is what every generation says, and which is so rarely actually true.
So- not my favorite Keegan book, but still enlightening.