Abstract :
The author has illuminated some of the questions which appear to cloud constructive builder - user relations. Each of the questions has a common feature: the problems will not be solved by extreme, one-way solutions; these problems are a feature of a new era of experimentation using large shared instruments. On the one hand, the objectives and the fundamental interest are just as "academic" as they have always been in the past when large tools were not required; on the other hand, the technical necessities are such that traditional academic methods cannot be blindly continued. In order to solve these problems there is a clear need for the builders to understand the problems of the users, and the users, the problems of the builders.
