Tiw, Woden, Thunor, Frig... these ancient northern deities gave their names to the very days of our week. Nevertheless most of us know far more of Mars, Mercury, Jupiter, Venus and the classical deities. Recent researches in archaeology and mythology have added to what was already a fairly consistent picture (largely derived from a twelfth-century Icelandic account) of the principal Scandinavian gods and godesses. This study is the work of a scholar who has long specialized in Norse and Germanic mythology. She describes the more familiar gods of war, of fertility, of the sky and the sea and the dead, and also discusses those most puzzling figures of Norse mythology – Heimdall, Balder and Loki. All these deities were worshipped in the Viking Age, and the author has endeavoured to relate their cults to daily life and to see why these pagan beliefs gave way in time to the Christian faith. **Hilda Ellis Davidson** studied Anglo-Saxon and Old Norse under the Chadwicks at Newnham College, Cambridge, where she took Firsts in English Literature and what was then known as Archaeology and Anthropology. She received her Ph. D. in 1940 for a thesis on beliefs about the dead in Old Norse literature. She lectured in English Language and Literature at Royal Holloway College and BirkBeck College in the University of London, and was elected a Fellow of the Society of the Antiquaries in 1950. In 1973 she became a Fellow of Lucy Cavendish College, Cambridge, where she was Vice-President from 1975 until 1980. She was president of the Folklore Society from 1973 to 1976, and General Editor of the nineteen Mistletoe Books published between 1974 and 1984. She is married with two children, and ten grandchildren, and lives in Cambridge.