Why was the meeting important?
Both men were involved in the evolution of atomic physics during a period of collaboration at Bohr's institute in Copenhagen. Why Heisenberg made the return visit from Nazi Germany to Copenhagen in 1941, and what the two men discussed remains a mystery. The two did meet again but never managed to resolve their differing versions of the meeting in Copenhagen. What is not in doubt is that their scientific contributions eventually lead to the invention of the atomic bomb.

WRITER & DIRECTOR   INTERVIEW
	Michael Frayn talks about Copenhagen    Director Howard Davies explains Copenhagen's plot    Davies describes adapting Michael Frayn's stage play    Davies details his vision for how the film would look

Are there any historical documents that shed any light on the mystery?
The mystery of what happened on that day in 1941 was illuminated earlier this year by the publication of previously unseen documents from the Niels Bohr archive. The fascinating archive website shows pictures of the original documents with a transcript and translation.

Are there any other interpretations of what happened that day?
Since the publication of documents from the Bohr archive, others have attempted to explain what might have been discussed.

CAST INTERVIEW
	Daniel Craig talks about his character Werner Heisenberg    Stephen Rea on theatre vs film and Michael Frayn's achievement in writing Copenhagen    Francesca Annis on the moral dilemma the play poses    Francesca Annis talks about her character Margrethe Bohr You will need RealPlayer to access the clips on the left. Visit WebWise for help downloading RealPlayer

Listen to scientist Hans Bethe remembering Niels Bohr and speaking about the significance of quantum theory.

Do I need to understand quantum mechanics to enjoy the play?
No, but it might help to understand a particle or two about the theories involved, and if you do want to find out a little more, try this simple timeline for historical context and scientific background.

And if that's not enough for you, there's Heisenberg's uncertainty principle to come to terms with and all the other theories that came before quantum theory.

But if you prefer a slightly more irreverent but still informative approach, try this explanation of the quantum world.

If you're stuck on a word or two, explore this wide-ranging glossary.

Who or what is Schroedinger's Cat?
Schroedinger's Cat is a now famous theory of the quantum world, proposed by Austrian physicist Erwin Schroedinger. While no real cats were kept in boxes, his theory suggested that objects could be in two places at the same time.

What else has Michael Frayn written?
Michael Frayn's most famous success is the 1982 play Noises Off. In an interview for this production of Copenhagen, he describes what made him tackle the complex subject of the quantum world.

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