The SIGNAL insurance companies have developed an expert system for the support of its customer sales service. It was introduced at the end of 1993 and is currently used by approximately 500 customer service representatives. It involves a counseling system, which enables customer sales personnel to produce high-quality benefit analyses at the point of sale. It is not only an information system for the agent but involves the customer in an active role (through the implementation of sales talks, the conscious visualisation of facts, the generation of natural language explanations etc.). Thus, the customer is not faced with a fait accompli but is actively involved in solving the problem. To meet these requirements, several AI techniques are used, as described further below. The application has increased sales efficiency, optimized customer contact time and decreased training requirements. The system is developed with KEE (and reimplemented in Allegro CL/PC) and runs on notebooks with 8 MB RAM.