Elfdalian is the language traditionally spoken in Övdaln (Älvdalen), central Sweden. Due to its linguistic differences to Swedish, coupled with the determination of the speech community, several attempts have been made to acquire an official recognition of Elfdalian as a minority language in Sweden. However, despite growing interest in documenting and revitalising Elfdalian, it is still regarded as a dialect. As one of the best-preserved members of a larger but lesser-known Dalecarlian (or Dalmål) sub-branch of the Scandinavian languages, Elfdalian is a unique language to study. The purpose of the grammar is to account for Late Classical, or 'Preserved', Elfdalian from linguistic, historical and sociolinguistic angles, and to make the language, including both its archaic and innovative features, accessible to a wider audience. The grammar has multiple target groups: people in Övdaln who wish to revitalise or reclaim their language in a more original form than the one it was transferred into through language decline and Swedish influence since the beginning of the twentieth century; those who wish to transmit the language to others through preschool, school or adult instruction; and likewise others who wish to study a lesser-known North Germanic language. Linguists may find Elfdalian interesting from the angles of comparative historical linguistics, language structure, as well as sociolinguistics and language planning.