A critical study of five historical armies offering solutions on how modern forces need to change to face contemporary threats. The most important mission of any government remains the defense of the state and its citizens. Traditionally, governments have used armed forces for this purpose. However, global events and the relative peace in Europe since 1989 have led most European governments to lose focus on defense.

Nevertheless, recent events have shown that war is now as brutal, violent, destructive, and widespread as ever. Governments need to fundamentally reconsider their relationship with their armies and soldiers. History provides us with numerous examples of states that have successfully restructured their armies, both on the battlefield and in how they relate to the state they are duty-bound to protect.

This book is about five armies that have adapted successfully: the army of the 4th century under Constantine the Great, the army of the 15th century under Sultan Mehmed II, Cromwell's New Model Army during the English Civil War, the Prussian Army of the Napoleonic Wars, and the U.S. Army during World War II.

Former senior military officer and renowned military historian Barney White-Spunner draws lessons from their experiences to establish timeless principles that remain equally relevant today as they were in the 4th century. It is a book about armies, their commitments, their organization, and their spirits.