A medieval military manual presents practical guidance for sovereigns and commanders on the conduct of war: assessments of just cause and the sovereign's authority to undertake campaigns, selection and duties of constables and captains, recruitment and training of knights and soldiers, organization and maneuvers of armies in the field, logistics for marches and river crossings, preparations for battle, siegecraft and fortification construction and defense, the design and use of engines and bombardment, mining and countermining, naval engagements, and legal and moral questions surrounding the right to wage and conduct warfare.