What battles have in common is human: the behaviors 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 compulson, 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 always a study of solidarity.
--John Keegan,
The Face of Battle