Although several most important contributions were made by the participants at our Cambridge meeting and the material organization ran most smoothly, I must confess that I was not satisfied, which may be partly due to personal reasons. Since, however, the few observations that I have to make apply also to most of our previous European meetings, I hope they may be of some use to the organizers of our future meetings. Indeed I think that the efficiency of our meetings is considerably less satisfactory than it could be. I have tried to analyse the reasons why this is so.