The bulk of the archive consists of Lars Onsager's papers which include correspondence, notes, manuscripts, reprints, books, photographs, etc. The Norwegian University of Science and Technology received this large collection in November 1997 from Lars Onsager's sons and daughter, Erling Fredrick Onsager, Inger Marie Woerheide, Hans Tanberg Onsager and Christian Carl Onsager. Onsager's writing desk, chair, diplomas, etc. were also included in the bequest. As the photograph shows, these items are now displayed at Lerchendal Gård, the headquarters of the Norwegian Academy of Technological Sciences. Onsager's widow, Margarethe Arledter Onsager, deposited most of Onsager's papers in Yale University Library in 1977-79, and several researchers (Stefan Machlup, Case Western Reserve University, Philip A. Lyons, William W. Watson, Raymond M. Fuoss, Andrew Patterson, Jr. and Derek Leaist, Yale University) helped to classify the material in Section II. A substantial part of this material was filmed in 1981, and is available on microfilm at Stirling Memorial Library, Yale University. Later, the collection was retrieved by the family and stored at the Onsager farm at Tilton, New Hampshire, until it was deposited in Trondheim. Supplementary material was added to the collection in 1998, in particular restricted material, private letters, obituaries, writings about Onsager, and more photographs. The archive now consists of 53 boxes and 2 oversize folders, altogether about 9 shelf metres. Text written by Monica Aase, Norwegian University of Science and Technology NTNU Library, 1999.