AIP History Center Newsletter
Volume XXXIX , No. 1, Spring 2007


Publication of the Collected Works
of Niels Bohr Completed
by Finn Aaserud

With the publication of the twelfth and final volume of the Niels Bohr Collected Works, one of the very greatest physicists of the twentieth century is brought before the public in one of the premier works of scholarship in modern history of science. Planning for the publication of the Collected Works began soon after Bohr’s death in 1962. The driving force behind the project was Bohr’s close collaborator, the Belgian physicist and historian of science Léon Rosenfeld, who was the first General Editor of the series. The first volume, covering the early years up to 1911, was published in 1972 with Jens Rud Nielsen (1894–1979) as editor. However, this was the only volume that Rosenfeld would see, for he died in 1974. The project, originally conceived as a ten-year effort, was not completed until well into the next century.

After an interim period with Rud Nielsen doing the brunt of the work, Erik Rüdinger was named General Editor in 1977. Rüdinger had served as Bohr’s scientific assistant for a brief period near the end of Bohr’s life. In Volume 5 (published 1985), the first under Rüdinger’s control, Rüdinger laid out the general editorial policy and practice that have been followed since. At the centennial of Bohr’s birth in 1985 the Niels Bohr Archive (NBA), which had existed in name for a number of years already, was formally established as an independent institution under the Danish Ministry of Education. Rüdinger continued as Director of NBA and General Editor of the Collected Works. When he retired as Director in 1989 to take up new challenges, three Volumes (7, 10 and 11) were still being planned for future publication. The project has just been completed under Finn Aaserud. Aaserud spent four years as postdoctoral Associate Historian at the AIP Center for History of Physics before moving to Copenhagen, where he succeeded Rüdinger as Director of NBA and General Editor.

Over the years, many prominent representatives of the several fields to which Bohr contributed have edited individual volumes in the series (see the full list, sidebar). Their work has been entirely voluntary and has more often than not been conducted concurrently with full-time jobs.

Whereas the first nine volumes are mainly devoted to Bohr’s
science, the remaining volumes contain Bohr’s publications outside physics. Volume 10 is devoted to his philosophy. The published documentation of Bohr’s other extra-scientific activities proved so large that the volume originally conceived as the last had to be divided into two separate ones. Volume 11 covers Bohr’s political interests and activities, notably his mission, in the wake of the atomic bomb, for what he called an “open world” between nations. Volume 12 is devoted to Bohr’s efforts as a popularizer of physics and, in particular, his published tributes to a variety of predecessors, teachers, colleagues, friends and family. Volumes 11 and 12 are particularly successful at bringing forth Niels Bohr as a person and in shedding light on aspects of Bohr’s activities that have so far remained undocumented in the English language.

The Collected Works claim completeness only with regard to Bohr’s publications. Manuscripts and letters are included selectively to illustrate particular points. The main language is English; any contribution previously available only in another language, typically Danish, appears in the original (often as facsimile) followed by a translation. Each of the various sections begins with an introduction, sometimes quite extensive, written by the editor of the volume in question. The volumes are illustrated with rare photos, and Bohr’s contributions, especially those directed exclusively to a Danish audience, are annotated for an international readership. Each volume includes an index. In addition, Volume 12 contains a chronological list of Bohr’s publications, with reference to where they can be found in the Collected Works.

At present, several of the volumes are out of print. Elsevier, the publisher, has promised to reprint the missing volumes by 2008 and to make the full set available at a favorable price. For further information contact Finn Aaserud, Niels Bohr Archive, Blegdamsvej 17, DK-2100 Copenhagen, Denmark; phone: +45 353 25220, email: The Archive’s homepage is


The Niels Bohr Collected Works. The first three Volumes are published under the name of Léon Rosenfeld (1904–1974) as General Editor, Volumes 5 through 9 are published under the general editorship of Erik Rüdinger (Volume 7 jointly with Finn Aaserud), and Finn Aaserud is General Editor of Volumes 10 through 12. The Volumes are published by North-Holland/Elsevier.

Vol. 1, Early Work (1905–1911), ed. J. Rud Nielsen, 1972.

Vol. 2, Work on Atomic Physics (1912–1917), ed. Ulrich Hoyer, 1981.

Vol. 3, The Correspondence Principle (1918–1923), ed. J. Rud Nielsen, 1976.

Vol. 4, The Periodic System (1920–1923), ed. J. Rud Nielsen, 1977.

Vol. 5, The Emergence of Quantum Mechanics (mainly 1924–1926), ed. Klaus Stolzenburg, 1984.

Vol. 6, Foundations of Quantum Physics I (1926–1932), ed. Jørgen Kalckar, 1985.

Vol. 7, Foundations of Quantum Physics II (1933–1958), ed. Jørgen Kalckar, 1996.

Vol. 8, The Penetration of Charged Particles through Matter (1912–1954), ed. Jens Thorsen, 1987.

Vol. 9, Nuclear Physics (1929–1952), ed. Rudolf Peierls, 1986.

Vol. 10, Complementarity beyond Physics (1928–1962), ed. David Favrholdt, 1999.

Vol. 11, The Political Arena (1934–1961), ed. Finn Aaserud, 2005.

Vol. 12, Popularization and People (1911–1962), ed. Finn Aaserud, 2006.


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