A BBC RADIO 4 BOOK OF THE WEEKAs winter comes and the hours of darkness overtake the light, we seek out warmth, good food, and good company. But beneath the jollity and bright enchantment of the festive season, there lurks a darker mood - one that has found expression over the centuries in a host of strange and unsettling traditions and lore. Here, Sarah Clegg takes us on a journey through midwinter to explore the lesser-known Christmas traditions, from English mummers plays and Austrian Krampus runs, to modern pagan rituals at Stonehenge and the night in Finland when a young girl is crowned with candles as St Lucy - a martyred Christian girl who also appears as a witch leading a procession of the dead.At wassails and hoodenings and winter gatherings, attended by ghastly, grinning horses, snatching monsters and mysterious visitors, we discover how these traditions originated and how they changed through the centuries, and we ask ourselves: if we can't keep the darkness entirely at bay, might it be fun to let a little in?