The work of this symposium and of its predecessors exemplifies the modern trend towards interdisciplinary research as a way of bringing increasingly specialized interests and fields of study to bear on particular topics. On the one hand we have the possibility, so well exemplified in the present case by the group excavating in Rijckholt, of combining the special knowledge of amateurs with the often more theoretical knowledge of professional archaeologists. On the other there is the possibility of bringing specialized natural science to bear on the solution of human problems. I would only like to stress that cooperation between specialists must be genuine, that is to say that specialist must maintain their integrity. Here in the Netherlands you have a fine example in the Biological-Archaeological Institute at Groningen of what I mean by genuine creative cooperation, as distinct from the bogus cooperation which exists when an archaeologist seeks to justify preconceived ideas by the selective use of scientific data.