Excerpts: Things Worth Remembering: How Warriors Prepare, H.L. McMaster, The Free Press

Yet the person from whom I gained the most insight into battle never served a day in the military. John Keegan was born in London in 1934, meaning he was too young to fight in the Second World War. He was then afflicted with orthopedic tuberculosis at the age of 13, which left him unable to join the British Army, despite his deep interest in military service from a young age. Instead, he became a military historian, delving deeply into the human and psychological dimensions of combat. My copy of his 1976 book, The Face of Battle, is replete with underlined passages and marginal notes.

It was my impending responsibilities as an officer that led me to study more purposefully, knowing that the seriousness with which I studied might save lives.

I read the book in 1984, just before graduating from West Point. It is a study of three pivotal battles that occurred centuries apart in the same patch of land in Europe: the battles of Agincourt (1415), Waterloo (1815), and the Somme (1916). Keegan reveals how technology, from the longbow to gunpowder to the machine gun, changed the face of battle. But what struck me the most was Keegan’s observation about what did not change across those five centuries. I memorized the following passage from the book’s conclusion:

What battles have in common is human: the behavior of men struggling to reconcile their instinct for self-preservation, their sense of honor and the achievement of some aim over which other men are ready to kill them. The study of battle is therefore always a study of fear and usually of courage, always of leadership, usually of obedience; always of compulsion, sometimes of insubordination; always of anxiety, sometimes of elation or catharsis; always of uncertainty and doubt, misinformation and misapprehension, usually also of faith and sometimes of vision; always of violence, sometimes also of cruelty, self-sacrifice, compassion; above all, it is always a study of solidarity and usually also of disintegration—for it is toward the disintegration of human groups that battle is directed.

The technology of battle has changed a great deal in the last hundred years, yet Keegan’s description of close combat would resonate with Ukrainian soldiers in the trenches of Pokrovsk, Israeli soldiers hunting Hamas in the rubbled neighborhoods of Gaza, and U.S. Special Operations forces raiding the remnants of ISIS in the rugged hills of northeastern Syria.

I read it just prior to becoming a young officer, and it convinced me that soldiers’ confidence—in their skills, in their leaders, and especially in one another—was the essential bulwark against fear and that emotion’s debilitating effects.