Book 11

Part I is devoted to Niels Bohr's mission to promote an "open world" between nations, that is, full sharing of information in the scientific and technical, as well as in the cultural spheres the scientific and technical, as well as in the cultural spheres. He started his mission immediately upon escaping from Nazi-occupied Denmark in the autumn of 1943, when he realized that the bomb was on the way to becoming a reality. As he wrote in 1944, he considered that the existence of the atomic bomb "would not only seem to necessitate but should also, due to the urgency of mutual confidence, facilitate" the realization of an open world. During the Second World War, while being actively involved in the Allied atomic bomb project, Bohr was able to obtain access to Prime Minister Churchill and President Roosevelt to promote his view. After the war he continued his confidential approaches to the statesmen while publishing more generally oriented articles on the issue.
Although Bohr put in as much work in appeals to the statesmen as in his other writings, they were not intended for publication. This has called for the inclusion of a greater number than in earlier volumes of the Collected Works of previously unpublished documents as well as a particularly extensive historical introduction written by the editor. The material adds up to a fascinating sotry of the political dedication and social responsibility ofone of the major scientists of the twentieth century.
Part II documents Bohr's other social and political activities, such as his long-time presidency in the Royal Danish Academy of Sciences and Letters and his promotion of the peaceful uses of atomic energy. Taking a broader approach than most of his other publications, these occasional writings, which are most often published versions of talks at public events, are particularly well suited to present Bohr to the general public, as a thinker as well as a person.

Book 12

The Niels Bohr Collected Works are now complete with the publication of Volume 12, Popularization and People (1911-1962).

Niels Bohr is generally regarded as one of the most influential physicists of the twentieth century. The following are only some of the high points. In 1913, Bohr proposed a revolutionary model of the atom breaking with classical conceptions of physics. In 1921, he established the Institute for Theoretical Physics at the University of Copenhagen, which became the centre for the new physics visited by the younger generation of physicists from all over the world. From 1927, he oversaw the development leading to the "Copenhagen interpretation" of quantum mechanics which for Bohr formed the foundation for an epistemology valid beyond physics based on Bohr's complementarity concept. In 1939, he explained the mechanism of nuclear fission. Finally, from 1943 until the end of his life in 1962, he carried out a personal political mission to establish an open world between nations which he considered to be necessary in view of the existence of the atomic bomb.

All these contributions are amply documented in the earlier volumes of the Niels Bohr Collected Works. This last volume documents Niels Bohr as a person and his efforts to explain quantum physics and its implications to physicists and non-physicists alike. While his activity over many years in the area of superconductivity illustrates his striving for synthesis in physics, his encyclopaedia articles and radio speech for Scandinavian gymnasium students document his effort to make quantum physics and its implications understandable to the general public. The bulk of the volume comprises Bohr's many published writings about his predecessors (for example Isaac Newton), teachers and colleagues (for example Ernest Rutherford and Albert Einstein), family and friends. These writings, which include several rare pieces of autobiogaphy, bring new perspectives to Bohr's life and document his substantial social network, both internationally and within his beloved Denmark.

In addition to Bohr's publications reproduced in Parts I and II, the volume includes a more brief Part III with selected correspondence, as well as an inventory of relevant manuscripts. It concludes with a bibliography of Bohr's many publications, chronologically arranged with references to where they can be found in the various volumes of the Collected Works. The volume is illustrated with many new photographs.