The Norwegian Knud Leem was the leading 18th-century specialist on Sami language and culture. On the initiative of Thomas von Westen (1683-1727), Leem arrived as a missionary in Finnmark, in 1725. Leem collected large quanitities of ethnological documentation on the Sami in his work as a vicar at Talvik and Alta, up until 1734. His observations and understanding of Sami behavior, living conditions and disposition are recorded in a publication called Beskrivelse over Finmarkens Lapper, deres Tungemaal, Levemaade og forrige afgudsdyrkelse. This was published in 1767, in Copenhagen. The Danish text is accompanied by a parallel Latin text. An extract was also released in German, in 1771 (Leipzig), and in English, in 1808 (London). The English volume was titled An Account of the Laplanders of Finmark, their Language, Manners, and Religion, and this was the first volume in the serial called A General Collection of the Best and Most Interesting Voyages and Travels in all Parts of the World, which was published from 1808-1814, by John Pinkerton.

Covering descriptions of the Finnmark Sami, the twenty-three chapters and one-hundred copperplates of this volume deal with numerous matters such as reindeer husbandry, extraction, language, dress, marriage, illness and nature worship. This significant and extensive portrayal of the indigenous people of northern Norway is regarded as a much more complete work than Schefferus's 1673 Lapponia. While Schefferus based his results on reports that were forwarded to him, Leem's work is based upon field studies that were conducted by himself. The publication of this work caused a sensation. It is still regarded as one of the most important ethnographical sources on the Sami people. Leem's account is characterized by its combination of piety and reasoning typical of the Enlightenment, and the publication's popularity can be tied to 18th-century inquisitiveness and interest in depictions of Europe's lesser known regions and people.

Knud Leem's aim with this work was, in the first place, to create a truthful and elaborate description of Sami manners and ways of thought. Secondly, Leem wished to set right some erroneous information in Schefferus's book and to enhance the Schefferus account (based upon information from Swedish Lappland) by concentrating on the Finnmark Sami. And thirdly, Leem wanted to correct many of the misconceptions that he found in La Martiniéres's book, Voyage des pais septentrionaux, which was published in 1671 (Paris). La Martiniéres "finds joy in letting his imagination run riot", according to the foreword in Leem's account; Leem was particularly offended because the Frenchman had accused everyone living in northern Norway of being sinister trolls.

Leem showed great sympathy and respect for the distinctive character of the Sami during his stay in Finnmark. He dressed in Sami clothing, spoke Sami and was highly loved by them.

From 1752 until his death in 1774, Knud Leem was a professor of the Sami language ("docens linguae lapponicae"), at the Seminarium Lapponicum in Trondheim, and even though his depiction of the Finnmark Sami must be regarded as his major work, Leem is also known for his studies of Sami grammar and language history.