This is a collection of essays, written by members of the British Commission for Military History. They examine key aspects of the experience of US and British armies, ranging from the American Civil War to Korea, Vietnam and the Falklands, to the Gulf War of 1991. Leadership and command are the essential elements that allow an army to function effectively in war. The exercise of command in particular is an under-researched area, and the essays make a major contribution to the understanding of this vital topic.