This is a dense and vivid account, thick with historical detail and incisive analysis and definitions. You can see why it is studied in military academies, but also as a primer for history students, ranging from the early middle ages to the nuclear era. It is written with the elegance one expects from Oxbridge academics.
First, after the chaos of the dark ages, a knightly culture emerged. This was based most importantly on the establishment of heavy, stone castles, where fighting forces could find safety and also, if they were so inclined, protect the peasants more consistently. Armed with the stirrup to ensure their balance with swords and heavier pikes, they developed a formidable new manner of fighting that combined mobility and enhanced lethality. Due to the costs of this equipment and fortification, knights reinforced their privilege with investments in arms races. Finally, there was a significant shift in Christian values: newly active popes promoted the notion of a moral code, an ethics of just war and personal responsibility. They fought with God on their side, much like the Muslims, their most dangerous adversaries. There were also rules of war, whereby captured knights could be ransomed after long captivity and without mistreatment, but also on the battlefield, where custom limited carnage and ferocity between aristocrats.
Second, as riches accumulated during the Gothic era, it became common to maintain standing armies, switching emphasis to mercenaries (the condottieri of the Renaissance). With bigger and bigger organization, princely states began to emerge; they were embryonic nations, mobilizing vast new resources in men and wealth. War became an entrepreneurial undertaking rather than an inflexible ritual, with spoils expected to pay the mercenaries, but also new resources for investment. Infantrymen could mass themselves with pikes, arrows, and the arquebus, which were able to quickly annihilate knights by attrition - their era was over. This led to the development of new tactics, resembling to a degree the standing armies of today, though less disciplined and specialized.
Third, war, discovery, piracy, and trade merged interchangeably at the moment that Europe entered its period of global expansion and exploration. Absolute sovereigns recognized the opportunities to enhance their power, sponsoring and aiding these adventurers, often equipping them with ships, arms, and men. Raleigh, Columbus, and Barberossa were the men of the age, mixing private wealth with national resources and developing naval tactics on a scale not seen since the Roman era. With bureaucracy, taxes, and investments, the state created institutions to support these undertakings.
Fourth, by the 18C, the state emerged to take full control of the armed forces, along with model created by Gustavus Adolophus, kind of Sweden and invader of Germany (ca. 1618). Fighting men were no longer a warrior caste or mercenaries, but professional agents of the state. They became more disciplined and increasingly specialized as new technologies emerged. Infantry formations were flat, saturation bombardment and smaller missiles came from newly mobile weapons (the flintlock and smaller cannons), and cavalry attacked in highly coordinated waves. With greater control, generals could transform their forces into fighting machines that obeyed a single strategic mind. These professionals became a self-contained subculture of the society, loyal to the leader.
Fifth, in the revolutionary age, fighting forces became more closely allied to ideals. Napoleon was the biggest actor here. This period was characterized by the emergence of autonomous divisions (as well as skirmishers and riflemen), which could move on multiple paths with greater speed and flexibility, yet were also capable of being organized into columns for more concentrated attacks at chosen points. While sometimes disorganized or with gaps in command structures when compared to the professional armies of the absolutist monarchs, they fought for freedom, opening the ranks to the talents of the lower classes who joined as professionals. War was becoming a contest between entire national economies, mobilizing entire populations, developing new technologies, and seeking natural endowments.
Sixth, with the development of railroads, steam ships, and communications technologies, the reach of the state was vastly increased, logistical capabilities enabled forces to be equipped and controlled on an unprecedented scale, and as a result the armed forces became an integral part of the political society; indeed, the military was a counter-revolutionary keeper of internal order with the rise of early industrial unrest and socialism. There was universal conscription, strong participation of the military hierarchy in the civil government, and the enhanced educational requirements (literacy, numeracy) of growing specialization. There were also superior weapons with enhanced killing precision: guns (spiral-grooved bores and breach-loading rifles) and ordnance from Krupp steel. Bismarck embodied all of these developments with the ascendance of the Prussian military machine. With this mass mobilization, the goal became to wear down by attrition of the economy of entire nations in prolonged total war. The result: World War I, in which soldiers were no longer the embodiment of national ideals but simple cannon fodder. In the next phase, technological development continued apace, with the complicating factor that ideologies seriously entered the competition for conquest and survival. Submarines, radar, sonar, and superior explosives became decisive; ballistic missiles and jet engines were invented. Hitler also perfected the blitzkrieg with a huge fleet of tanks, in which thrusts of force were used to cut off communications and supplies while the enemy was encircled as a prelude to mass destruction if unsuccessful. WWII devolved into a war attrition.
Seventh, there is the nuclear era, a quantum leap in destructive capability and a further shrinking of the importance of ground troops - a massive supporting bureaucracy was moving to the fore. Europe was no longer at the center of action, but became an observer of the superpowers. Not only did total war become unthinkable, but the distance of the young cannon fodder from considering military careers as meaningful - made worse by the horror of guerilla movements - created a gap between the military and civil society. This is the only chapter that I found weak and too succinct, grafted on. It is also outdated with the end of the cold war and the rise of tribal conflicts, such as that in Iraq.
In spite of the weakness of the chapter on nuclear strategy, this book is a wonderful tour de force. I had to read it several times, underlining it like I was a college student. I would have liked more on strategy and its relation to politics, but it is a brief book and that would require more scope than was possible in this format. Recommended. I know this review is too long, but I wanted to record the essence of what I learned, which was a lot.