How was the Norse Navigator able to shape his course across the North Atlantic long before the invention of the magnetic compass? This book tells the story of the Viking Sun Compass and how it allowed the Vikings to sail across the Atlantic. In 1948, the Danish archaeologist C.L. Vebæk found the remains of a small wooden disc at the Viking Age site of Uunartoq in Greenland. Since then the Master mariners Carl V. Sver and Sen Thirslund have interpreted this find as a navigational instrument. This book is the essence of more than forty years of archaeological studies, discussions and practical sea-going experiments. The author gives a full account of the history of the find and demonstrates convincingly how Viking Age Navigators could make use of this and other simple devices in order to find their way across the vastness of the Northern Atlantic.