What is the author's style in The Mask of Command by John Keegan?

Keegan is best known for his comprehensive works on worldwide military history, with particular focus on military figures and battles from fourteenth through twenty-first centuries. In addition to dissecting the technical aspects of warfare, Keegan is also known for uncovering the psychology used in battle. As irony would have it, Keegan was too young to serve in WWII and would have been deemed ineligible anyway due to a bout with tuberculosis as a child.