Asatru (literally translated as "faith of the Gods") is a NeoPagan path based on Norse mythology. The difference between Asatru and most other NeoPagan paths, perhaps particularly Wicca is that it is a reconstructed religion which seeks to align as closely as possible with the traditions that have gone before. It is a reconstructed religion, a modern revival of ancient beliefs - Asatru is not a reworking or reimagining of an old path - modern adherents seek to follow the path as closely as possible of those who have gone before.
Asatru is sometimes referred to as Odinism (Odin being the father figure of the Norse Gods) although this term is not consistent with many followers of the faith as many believe it elevates Odin to a disproportionate importance and that all the Gods have a key role to play in the faith, not just Odin. Asatru is also often referred to a Norse or Germanic Heathenry. The description of Heathenry implies a non doctrine based relationship with deity, a definition that does fit Asatru but which is essentialy a more general term governing other strands of independent community relationships with deity as well.
Asatru is a polytheistic religion, evolved from Viking times, worshipping the Gods of the Norse pantheon though worship of deities from other pantheons, particularly the Celtic Gods, is not unheard of. Again, in a break with other NeoPagan paths, Asatru does not follow an interpretative understanding of the Gods, the Gods are seen very much as individuals with their own tangible history. Followers of Asatru believe that humanity is directly descended from the Gods and that the Gods Odin, Vili and Ve descended to Earth and created the first humans by breathing life into two trees. The belief is literal not allegorical.
There is a strong emphasis on communing with ancestors and honouring those who have gone before. This is an extremely important part of the faith due to the determination to walk the path of their ancestors. The ancestors are honoured for the giving of the spiritual gifts which allow followers of Asatru to practise their faith into the modern age.
Asatru is less of a magical path than it is a spiritual path. Unlike Wicca, Shamanism and Druidism there is much less emphasis on the use of magic. The magic that is practised is generally associated with runes and the runic alphabet. In Asatru the runes are used as much for magic as they are for divination. However the elaborate magic rituals of Wicca or the crossing to other worlds of Shamanism are not seen as a primary element of the faith. The Runic alphabet is believed to have its origins in the early Scandinavian worshippers and legend has it that the runes were the wisdom sought by Odin after hanging on the world tree Yggdrassil for nine nights. He brought the runes back to the rest of the Gods who in turn passed them onto humankind.
In the mid 1970s Iceland - one of the Scandinavian countries from which Asatru was established - declared it to be the formal religion of the country. This is an important milestone in the credibility of the religion and also in its claim to not simply be another of the Neopagan paths.
Sacrifice is an important element of the Asatru religion and the most common form of sacrifice is called the blot. This was traditionally the ritual slaying of an animal as an offering to the Gods but more takes the form of a feast in modern times. The Asatru priest, known as the Gothat leads the blot. He is also responsible for keeping the religion alive in the hearts and minds of the people and for his role in helping to reconstruct the paths of the ancestors.
Several of the commonly celebrate eight Sabbats are observed by followers of Asatru. The names differ (Charming of the Plow for Imbolc, Freyfaxi for Lammas...) but the essential idea of celebrating the changing of the seasons remains the same. The festivals of Midsummer and Winter Nights (Yule) marking the middle of the Summer and the middle of the Winter (the longest day and the longest night) are key festivals within the faith. Asatru also celebrates Einherjar on November 11th which honours those who have died in battle. This is close to the Witch observation of Samhain - the day of the dead - with a similar focus on those who have passed.
Image http://www.deviantart.com/art/Yggdrasil-The-World-Tree-59953621 (Duende14)