Vikings at War is a sumptuous depiction of how the Vikings waged war: their weapons technology, offensive and defensive warfare, military traditions and tactics, their fortifications, ships and command structure. It also portrays the Viking raids and conquest campaigns that brought the Vikings to virtually every corner of Europe and even to America. Between the 9th and 11the century, Viking ships landed on almost every shore in the Western world. Viking ravages united the Spanish kingdoms and stopped Charlemagne and the Franks' advance in Europe. Wherever Viking ships roamed, enormous suffering followed in their wake, but the encounter between cultures changed both European and Nordic societies.

Employing unorthodox and unpredictable strategies, which were hard for more organized forces to respond to, the most crucial element of the Vikings' success was their basic strategy of evading the enemy by arriving by sea, then attacking quickly and with great force before withdrawing quickly. The warrior class dominated in a militarized society. Honor was everything, and breaking promises and ruining one's posthumous reputation was considered worse than death itself. If a man offended another man's honor, the only way out was blood revenge.

Vikings at War provides a vivid account of the Viking art of war, weapons and the history of their conquests with over 380 colour illustrations including beautiful reconstruction drawings, maps, cross-section drawings of ships, line-drawings of fortifications, battle plan reconstructions and photos of surviving artefacts including weapons and jewellery.