 Bienvenue à ce colloque de clôture de notre trimestre sur le monde quantique qui était organisé par mes collègues de l'IHS et je l'ai aidé un peu. Si vous voulez regarder les exposés qu'il y avait, vous les trouverez sur une page web de l'IHS. Voilà, alors j'aimerais commencer avec quelques remerciements. Je ne suis pas dit ici donc j'aimerais explicitement remercier tous les conférenciers qui ont parlé pendant ce trimestre. La plupart des exposés étaient vraiment superbes. Probablement, ils ont pris les exposés qu'on va écouter maintenant et c'est vraiment les conférenciers qui ont fait de cet exercice un certain succès. J'aimerais aussi remercier mes collègues et le directeur de l'IHS de m'avoir donné la possibilité de réaliser cette série de séminaires dans un cadre idéal. Et finalement, je remercie tous les membres du staff de l'IHS et en particulier Cécile Gourg et Isabette Jasseron qui m'ont aidé avec des choses pratiques. Alors, quand nous avons commencé les exposés, j'ai montré ce slide avec le titre ABC in Quantum Mechanics and I will now recall what it means. It's supposed to stand for Against Babylonian Confusion in Quantum Mechanics and I had associated a certain hope with our programme and it was formulated as follows. The purpose of our programme is to review some basic experimental facts and theoretical ideas about quantum mechanics with the hope that this will help us improve our understanding of this theory and reduce some of the confusion surrounding its meaning and interpretation. So we will have to think about whether we have accomplished our goal. Certainly the problems we are fighting with have led to fairly emotional discussions but I think in the end certain things got clarified. Dibo will maybe comment on that. So what has been accomplished? So it's time to ask whether we have reached our goal and I would like to read a quote. Once again we have to admit the curtain has been pulled and all questions remain open. I think this is a little too pessimistic. I feel we have done reasonably well in clarifying some aspects of quantum mechanics. At least I myself feel I understand a little more than I did some time ago. But of course there are sufficiently many features of this wonderful theory that continue to be somewhat mysterious and so we can propose continuant notre balade à travers le monde grandique il reste du travail à faire. And this is if you want to see the German version of my quote. Here it is, it is due to Bertolt Brecht from a theatre play that is called The Good Human Being from Sichuan. I think it's actually a very interesting play. And I would like to remind you of what I said on day one. We should try to become a little more active politically again and get engaged. So thank you and it's time to pass to the first lecture which will be presented by Klaus Friedenhagen.