In June 1984 a total of 169 physicians, scientists and students assembled in the now familiar and much-loved lair in the Wilsede Luneberg Heath near Hamburg, Germany, for the sixth biennial conference on Modern Trends in Human Leukaemia. This meeting, conducted by Prof. Rolf Neth in his own inimitable style, has established itself as one ofthe major events in the all too crowded programme of international conferences on leukaemia, cancer and related topics. Some may ponder why, with its "rustic" setting - flies, equine deposits, and lack of easy exit -, Wilsede has such an irresistible and persistent lure for so many of the world's top practitioners ofleukaemia research? The an- swer is, I suspect, a cocktail of Rolfs extraordinary charm, the pleasure of meeting friends and colleagues in a uniquely informal and relaxed atmo- sphere and the special style of the proceedings themselves, which focus on the evaluation of ideas and hypotheses rather than the cataloguing of data.