In September 1941, still the early years of World War II, Werner Heisenberg travelled to Copenhagen, in German-occupied Denmark to meet his long-time friend and mentor Niels Bohr. The meeting that took place along a tree-lined path in the large and secluded Fælledpark just behind Bohr's institute, has been shrouded in controversy and questions, since neither participant ever disclosed the nature of their conversation nor the real purpose of Heisenberg's visit. The locale was carefully chosen to maintain total confidentiality.

Michael Frayn's drama ‘Copenhagen’, which opened to rave reviews at London's National Theatre in May 1998, sparked a renewal of interest in the encounter, as it took place after the realisation by scientists that nuclear fission provided a means of producing weapons of unprecedented devastating power. The play has since been performed all over the world, including two shows at the National Institute of Advanced Studies, Bangalore. It is guessed that a record number of 1,000,000 people have watched it, many more than the total number of physicists who have ever lived. The success of the play as drama is undeniable. Its historical accuracy, the accuracy of its presentation of physics and the scientific/philosophical ideas around which it has been structured have engaged the attention of scientists and sociologists and have occasioned many debates.

In March 2002, a symposium was organised in Washington DC to present and discuss interpretations on the subject of the play and of the previously private documents, released by the Niels Bohr Archive in Copenhagen in February 2002, which shed some light on the matter. Heisenberg's son, Jochen Heisenberg, currently a Professor of Physics in the University of New Hampshire, Durham, was invited to speak on the occasion. Reproduced below are his personal reflections on his father Werner Heisenberg.

The complete details of the symposium are available at the following website:
http://web.gsuc.cuny.edu/ashp/nml/copenhagen.

Facsimile of the original documents of the Bohr Archive along with their English translations
are available at:
http://www.nba.nbi.dk.

We thank Professor Jochen Heisenberg for kindly granting us permission to reproduce in full his article.