I've had much help with this project. First of all (once again) from Sarah Haffner, who got me off on the right foot as soon as I told her what I had in mind, by recommending me to read Arnulf Baring's Machtwechsel, and who subsequently supplied me with further parcels of books and help in translating a number of particularly awkward phrases. Peter Merseburger, the political journalist, who was working in Bonn during the Brandt Chancellorship and whose own biography of Brandt has since appeared, gave me a great deal of patient advice. He also introduced me to Klaus Harpprecht, Brandt's speechwriter, and asked his old colleague Fritz Pleitgen to open the film archives of Westdeutscher Rundfunk in Cologne for me.

Eva Giesel, a colleague of my German play agent Ursula Pegler, spent much time, energy and ingenuity making contacts and inquiries on my behalf. I originally expected the play to lay more emphasis on the Guillaumes' trial, and Frau Giesel worked particularly hard at putting me in touch with officials of the court where it took place, the Oberlandesgericht in Dusseldorf. My thanks, too, to Herr Bundesanswalt Lampe, in the office of the Generalbundesanwalt in Karlsruhe, who explained some of the basics of German law to me, and to Professor Peter Brandt, Willy Brandt's eldest son, who most kindly offered to see me, though in the end I decided it might inhibit me; to Frau Gertrud Lenz in the Friedrich-Ebert-Stiftung in Bad Godesberg, where the Brandt papers are lodged; to Fritz Pleitgen at WDR; to ZDF for the text of Guido Knopp's interview with Guillaume; to Frau Marianne Wichert-Quoirin, who covered Federal politics in Bonn and the Guillaume trial in Dusseldorf for the Kölner Stadt-Anzeiger, and to Finn Aaserud for the Norwegian.

The amount of material available turned out to be oceanic, and for the first time in my life, when I finally had to recognise that I was drowning, I got the help of a research assistant. My choice - Stefan Kroner, the dramaturg who had worked on one of the German productions of Copenhagen - turned out to be inspired. He was not only unbelievably quick and industrious, but had an uncanny ability to guess what I should find useful. He plunged into the archive of the Friedrich-Ebert-Stiftung, and of WDR in Cologne, and reduced the tons of press-cuttings and weeks of newsreel to proportions I could just about manage. He found books long out of print, and trawled information from the huge deposits of old Stasi files in Berlin (still not fully explored, and a rich potential source of fossil fuel). We also had a delightful trip around the Rhineland together, to see where it all happened and to visit the various archives.

For anyone interested in finding out more about the case itself, or the personalities and politics of the period, the following is a short list of the more easily available material:

General