Jens Braage Halvorsen was a Norwegian librarian, magazine editor and literary historian.

He edited the magazine Ny Illustreret Tidende from 1880 to 1883. He is particularly known for his principal work, the encyclopedia of Norwegian

Norwegian language

Norwegian is a North Germanic language spoken primarily in Norway, where it is the official language. Together with Swedish and Danish, Norwegian forms a continuum of more or less mutually intelligible local and regional variants .These Scandinavian languages together with the Faroese language...

 writers, Norsk forfatterlexikon, which was issued from 1881 until his death. The encyclopedia was finished in 1908 by Halvdan Koht

Halvdan Koht

Halvdan Koht was a Norwegian historian and politician representing the Labour Party.As a politician he served as the Norwegian Minister of Foreign Affairs from 1935 to 1941. He was never elected as a member of the Parliament of Norway, but was a member of Bærum municipal council in 1917–1919 and...

.

Halvorsen was Norwegian editor for the first edition of the encyclopedia Salmonsens Konversations-Lexikon

Salmonsens Konversationsleksikon

Salmonsens Konversationsleksikon is a Danish encyclopedia that has been published in several editions.The first edition, Salmonsens Store Illustrerede Konversationsleksikon was published in nineteen volumes 1893-1911 by Brødrene Salmonsens Forlag, and named after the publisher Isaac Salmonsen...

. He was decorated Knight of the Royal Norwegian Order of St. Olav in 1896.