As in other countries of the far north, the art of preserving food for the winter has had great importance. The tradition of a special ‘month of sour things’ in the winter, when people gathered to feast on preserved foods, was revived in the 20th century. Many of the whey-preserved items are offal—lamb’s hearts, testicles, feet, etc. Smoked items include lamb, sausages, tongues, and fish such as salmon and trout. There are also some methods of preservation which seem quite strange. The flesh of the huge Greenland shark, Somniosus microcephalus, is not edible when raw and untreated, but, if buried and allowed to ferment, it becomes safe to eat, although very smelly. It is perhaps not surprising that hákarl, as the product is known, is sold in fairly small pieces, with the crinkled black skin looking like a fragment from one of Iceland’s lava beds. Skate wings are also fermented, especially for St Thorlak’s Day (23 December), and the skate is sometimes boiled in the cooking liquid from the smoked lamb that is traditional Christmas food. Other fish, e.g. halibut, are dried and eaten raw, with a little butter, indeed there is a tradition of using dried fish in place of bread. However, the truly great story about dried fish involves a controversy about drying cods’ heads. In 1914 a banker called Gunnarsson boldly attacked this cherished tradition as being uneconomical if the full true cost of drying one head was considered. The nation was shocked but eleven years passed before the Director of the National Library, Guðmundur Finnbogason, was ready to deliver his massive and crushing response, deploying mathematical, social, political, moral, linguistic, historical, and hygienic arguments.