Nordisk familjebok (Swedish: [ˈnuːɖɪsk faˈmɪljəˈbuːk], Nordic Family Book) is a Swedish encyclopedia that was published in print form between 1876 and 1957, and that is now fully available in digital form via Project Runeberg at Linköping University.
The first edition of Nordisk familjebok was published in 20 volumes between 1876 and 1899, and is known as the "Idun edition" because it bears a picture of Idun, the Norse mythologic goddess of spring and rejuvenation, on its cover. This was published during almost a quarter of a century, and particularly the first ten volumes contain material which are not seen in later editions. A good example of this is found in the end of the Berlin article (which is included in the second volume, from 1878), where the author finishes his article by talking about the public decency and morality, which he finds to be very poor. The author continues by complaining about there being a very lazy interest in religious matters and concludes: "to all these joint circumstances, one can hardly defend oneself against the thought of future threatening dangers".
The second edition, popularly known as Uggleupplagan ("The Owl Edition") because of an owl image on its cover, was published between 1904 and 1926 in 38 volumes, and is the most comprehensive encyclopedia published in the Swedish language. 
The third edition had 17 volumes and was published between 1924 and 1937. Another three supplementary volumes were published in 1937, 1938 and in 1939. The supplement covers for instance the Spanish Civil War and a heavy update on Adolf Hitler, but nothing about Germany's war on Poland nor are later events are mentioned. A second printing of the entire third edition was published between 1941 and 1944. Nothing essential is changed in the second printing, but quite a lot of one side portraits (still in black and white), coloured maps of "World cities", European countries, continents, Swedish provinces and cities are added together with a few topics, like a collection of national flags. All the added material are on unnumbered pages, presumably a technical printing solution (so already printed books did not require re-numbering). This edition is usually called "the 1930s edition" and are of brown colour when looking at them on a shelf.
- , accessed 22 April 2015.