Book excerpt: He begins by analysing the sources for our knowledge of the military history of the period, assessing their reliability: some chroniclers exaggerate, others are careful observers or have access to official records. There follows an examination of the constituent parts of the medieval army, knights and footsoldiers, equipment and terms of service, behaviour on the field, and psychology, before the problematic question of medieval tactics is addressed through analysis of accounts of a series of major battles. Strategy is discussed in the context of these battles: whether to seek battle, fight a defensive war, or attempt a war of conquest.