I have just finished reading Paddy Griffiths 'The Viking Art of War'. As always with this fine historian he gives the reader much more than a narrative history. In this book he explains who the Vikings were, the causes of their expansion and how they used their strategic mobility. He then sets out their strategy, battle tactics, army composition and arms and armour.
Sadly he debunks many Viking myths like the Berserkers and Jomsvikings. Recognising that the historical sources are limited for this period, he none the less sets out a more credible explanation of Viking strategy and tactics than the well known popular images. He does this by applying modern military thinking to challenges the Vikings faced.
The Vikings were not the supermen of myth. In fact they probably lost more battles than they won. This is not surprising when you consider that they fought in a similar way, with similar weapons as their opponents. They brought few if any technological developments, even their ships were only a modest improvement on existing naval architecture. They were effective in small raids when the opposition was not organised to resist them and on the fringes of Europe. They also fought amongst themselves as often as their neighbours. National organisation was at best a loose control and they rarely organised into the 'great armies' that did have a major impact on the history of France and England in particular. They were effectively countered by states that used fortifications and the strategic mobility of mounted troops.
What they did possess was exceptional energy and enthusiasm and whilst they have left a small historical footprint, their achievements were significant. Vikings fought as far away as the Middle East, travelling vast distances in modest sailing boats by modern standards. They excelled at deception and surprise and their strategic mobility caused the great empires of the period huge problems. In the places they occupied, rather than simply raided, they assimilated quickly into the local population. Most famously of course they morphed into the Normans, who themselves ranged far and wide.
Great book and highly recommended.